/*
** 2008 August 18
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains routines used for walking the parser tree and
** resolve all identifiers by associating them with a particular
** table and column.
*/
#include "sqliteInt.h"
#include <stdlib.h>
#include <string.h>
/*
** Turn the pExpr expression into an alias for the iCol-th column of the
** result set in pEList.
**
** If the result set column is a simple column reference, then this routine
** makes an exact copy. But for any other kind of expression, this
** routine make a copy of the result set column as the argument to the
** TK_AS operator. The TK_AS operator causes the expression to be
** evaluated just once and then reused for each alias.
**
** The reason for suppressing the TK_AS term when the expression is a simple
** column reference is so that the column reference will be recognized as
** usable by indices within the WHERE clause processing logic.
**
** Hack: The TK_AS operator is inhibited if zType[0]=='G'. This means
** that in a GROUP BY clause, the expression is evaluated twice. Hence:
**
** SELECT random()%5 AS x, count(*) FROM tab GROUP BY x
**
** Is equivalent to:
**
** SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5
**
** The result of random()%5 in the GROUP BY clause is probably different
** from the result in the result-set. We might fix this someday. Or
** then again, we might not...
*/
static void resolveAlias(
Parse *pParse, /* Parsing context */
ExprList *pEList, /* A result set */
int iCol, /* A column in the result set. 0..pEList->nExpr-1 */
Expr *pExpr, /* Transform this into an alias to the result set */
const char *zType /* "GROUP" or "ORDER" or "" */
){
Expr *pOrig; /* The iCol-th column of the result set */
Expr *pDup; /* Copy of pOrig */
sqlite3 *db; /* The database connection */
assert( iCol>=0 && iCol<pEList->nExpr );
pOrig = pEList->a[iCol].pExpr;
assert( pOrig!=0 );
assert( pOrig->flags & EP_Resolved );
db = pParse->db;
if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){
pDup = sqlite3ExprDup(db, pOrig, 0);
pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0);
if( pDup==0 ) return;
if( pEList->a[iCol].iAlias==0 ){
pEList->a[iCol].iAlias = (u16)(++pParse->nAlias);
}
pDup->iTable = pEList->a[iCol].iAlias;
}else if( ExprHasProperty(pOrig, EP_IntValue) || pOrig->u.zToken==0 ){
pDup = sqlite3ExprDup(db, pOrig, 0);
if( pDup==0 ) return;
}else{
char *zToken = pOrig->u.zToken;
assert( zToken!=0 );
pOrig->u.zToken = 0;
pDup = sqlite3ExprDup(db, pOrig, 0);
pOrig->u.zToken = zToken;
if( pDup==0 ) return;
assert( (pDup->flags & (EP_Reduced|EP_TokenOnly))==0 );
pDup->flags2 |= EP2_MallocedToken;
pDup->u.zToken = sqlite3DbStrDup(db, zToken);
}
if( pExpr->flags & EP_ExpCollate ){
pDup->pColl = pExpr->pColl;
pDup->flags |= EP_ExpCollate;
}
/* Before calling sqlite3ExprDelete(), set the EP_Static flag. This
** prevents ExprDelete() from deleting the Expr structure itself,
** allowing it to be repopulated by the memcpy() on the following line.
*/
ExprSetProperty(pExpr, EP_Static);
sqlite3ExprDelete(db, pExpr);
memcpy(pExpr, pDup, sizeof(*pExpr));
sqlite3DbFree(db, pDup);
}
/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr
** expression node refer back to that source column. The following changes
** are made to pExpr:
**
** pExpr->iDb Set the index in db->aDb[] of the database X
** (even if X is implied).
** pExpr->iTable Set to the cursor number for the table obtained
** from pSrcList.
** pExpr->pTab Points to the Table structure of X.Y (even if
** X and/or Y are implied.)
** pExpr->iColumn Set to the column number within the table.
** pExpr->op Set to TK_COLUMN.
** pExpr->pLeft Any expression this points to is deleted
** pExpr->pRight Any expression this points to is deleted.
**
** The zDb variable is the name of the database (the "X"). This value may be
** NULL meaning that name is of the form Y.Z or Z. Any available database
** can be used. The zTable variable is the name of the table (the "Y"). This
** value can be NULL if zDb is also NULL. If zTable is NULL it
** means that the form of the name is Z and that columns from any table
** can be used.
**
** If the name cannot be resolved unambiguously, leave an error message
** in pParse and return WRC_Abort. Return WRC_Prune on success.
*/
static int lookupName(
Parse *pParse, /* The parsing context */
const char *zDb, /* Name of the database containing table, or NULL */
const char *zTab, /* Name of table containing column, or NULL */
const char *zCol, /* Name of the column. */
NameContext *pNC, /* The name context used to resolve the name */
Expr *pExpr /* Make this EXPR node point to the selected column */
){
int i, j; /* Loop counters */
int cnt = 0; /* Number of matching column names */
int cntTab = 0; /* Number of matching table names */
sqlite3 *db = pParse->db; /* The database connection */
struct SrcList_item *pItem; /* Use for looping over pSrcList items */
struct SrcList_item *pMatch = 0; /* The matching pSrcList item */
NameContext *pTopNC = pNC; /* First namecontext in the list */
Schema *pSchema = 0; /* Schema of the expression */
int isTrigger = 0;
assert( pNC ); /* the name context cannot be NULL. */
assert( zCol ); /* The Z in X.Y.Z cannot be NULL */
assert( ~ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_Reduced) );
/* Initialize the node to no-match */
pExpr->iTable = -1;
pExpr->pTab = 0;
ExprSetIrreducible(pExpr);
/* Start at the inner-most context and move outward until a match is found */
while( pNC && cnt==0 ){
ExprList *pEList;
SrcList *pSrcList = pNC->pSrcList;
if( pSrcList ){
for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
Table *pTab;
int iDb;
Column *pCol;
pTab = pItem->pTab;
assert( pTab!=0 && pTab->zName!=0 );
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
assert( pTab->nCol>0 );
if( zTab ){
if( pItem->zAlias ){
char *zTabName = pItem->zAlias;
if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
}else{
char *zTabName = pTab->zName;
if( NEVER(zTabName==0) || sqlite3StrICmp(zTabName, zTab)!=0 ){
continue;
}
if( zDb!=0 && sqlite3StrICmp(db->aDb[iDb].zName, zDb)!=0 ){
continue;
}
}
}
if( 0==(cntTab++) ){
pExpr->iTable = pItem->iCursor;
pExpr->pTab = pTab;
pSchema = pTab->pSchema;
pMatch = pItem;
}
for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
IdList *pUsing;
cnt++;
pExpr->iTable = pItem->iCursor;
pExpr->pTab = pTab;
pMatch = pItem;
pSchema = pTab->pSchema;
/* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
if( i<pSrcList->nSrc-1 ){
if( pItem[1].jointype & JT_NATURAL ){
/* If this match occurred in the left table of a natural join,
** then skip the right table to avoid a duplicate match */
pItem++;
i++;
}else if( (pUsing = pItem[1].pUsing)!=0 ){
/* If this match occurs on a column that is in the USING clause
** of a join, skip the search of the right table of the join
** to avoid a duplicate match there. */
int k;
for(k=0; k<pUsing->nId; k++){
if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){
pItem++;
i++;
break;
}
}
}
}
break;
}
}
}
}
#ifndef SQLITE_OMIT_TRIGGER
/* If we have not already resolved the name, then maybe
** it is a new.* or old.* trigger argument reference
*/
if( zDb==0 && zTab!=0 && cnt==0 && pParse->pTriggerTab!=0 ){
int op = pParse->eTriggerOp;
Table *pTab = 0;
assert( op==TK_DELETE || op==TK_UPDATE || op==TK_INSERT );
if( op!=TK_DELETE && sqlite3StrICmp("new",zTab) == 0 ){
pExpr->iTable = 1;
pTab = pParse->pTriggerTab;
}else if( op!=TK_INSERT && sqlite3StrICmp("old",zTab)==0 ){
pExpr->iTable = 0;
pTab = pParse->pTriggerTab;
}
if( pTab ){
int iCol;
pSchema = pTab->pSchema;
cntTab++;
for(iCol=0; iCol<pTab->nCol; iCol++){
Column *pCol = &pTab->aCol[iCol];
if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
if( iCol==pTab->iPKey ){
iCol = -1;
}
break;
}
}
if( iCol>=pTab->nCol && sqlite3IsRowid(zCol) ){
iCol = -1; /* IMP: R-44911-55124 */
}
if( iCol<pTab->nCol ){
cnt++;
if( iCol<0 ){
pExpr->affinity = SQLITE_AFF_INTEGER;
}else if( pExpr->iTable==0 ){
testcase( iCol==31 );
testcase( iCol==32 );
pParse->oldmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
}else{
testcase( iCol==31 );
testcase( iCol==32 );
pParse->newmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
}
pExpr->iColumn = (i16)iCol;
pExpr->pTab = pTab;
isTrigger = 1;
}
}
}
#endif /* !defined(SQLITE_OMIT_TRIGGER) */
/*
** Perhaps the name is a reference to the ROWID
*/
if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){
cnt = 1;
pExpr->iColumn = -1; /* IMP: R-44911-55124 */
pExpr->affinity = SQLITE_AFF_INTEGER;
}
/*
** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
** might refer to an result-set alias. This happens, for example, when
** we are resolving names in the WHERE clause of the following command:
**
** SELECT a+b AS x FROM table WHERE x<10;
**
** In cases like this, replace pExpr with a copy of the expression that
** forms the result set entry ("a+b" in the example) and return immediately.
** Note that the expression in the result set should have already been
** resolved by the time the WHERE clause is resolved.
*/
if( cnt==0 && (pEList = pNC->pEList)!=0 && zTab==0 ){
for(j=0; j<pEList->nExpr; j++){
char *zAs = pEList->a[j].zName;
if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
Expr *pOrig;
assert( pExpr->pLeft==0 && pExpr->pRight==0 );
assert( pExpr->x.pList==0 );
assert( pExpr->x.pSelect==0 );
pOrig = pEList->a[j].pExpr;
if( !pNC->allowAgg && ExprHasProperty(pOrig, EP_Agg) ){
sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
return WRC_Abort;
}
resolveAlias(pParse, pEList, j, pExpr, "");
cnt = 1;
pMatch = 0;
assert( zTab==0 && zDb==0 );
goto lookupname_end;
}
}
}
/* Advance to the next name context. The loop will exit when either
** we have a match (cnt>0) or when we run out of name contexts.
*/
if( cnt==0 ){
pNC = pNC->pNext;
}
}
/*
** If X and Y are NULL (in other words if only the column name Z is
** supplied) and the value of Z is enclosed in double-quotes, then
** Z is a string literal if it doesn't match any column names. In that
** case, we need to return right away and not make any changes to
** pExpr.
**
** Because no reference was made to outer contexts, the pNC->nRef
** fields are not changed in any context.
*/
if( cnt==0 && zTab==0 && ExprHasProperty(pExpr,EP_DblQuoted) ){
pExpr->op = TK_STRING;
pExpr->pTab = 0;
return WRC_Prune;
}
/*
** cnt==0 means there was not match. cnt>1 means there were two or
** more matches. Either way, we have an error.
*/
if( cnt!=1 ){
const char *zErr;
zErr = cnt==0 ? "no such column" : "ambiguous column name";
if( zDb ){
sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
}else if( zTab ){
sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
}else{
sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
}
pParse->checkSchema = 1;
pTopNC->nErr++;
}
/* If a column from a table in pSrcList is referenced, then record
** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes
** bit 0 to be set. Column 1 sets bit 1. And so forth. If the
** column number is greater than the number of bits in the bitmask
** then set the high-order bit of the bitmask.
*/
if( pExpr->iColumn>=0 && pMatch!=0 ){
int n = pExpr->iColumn;
testcase( n==BMS-1 );
if( n>=BMS ){
n = BMS-1;
}
assert( pMatch->iCursor==pExpr->iTable );
pMatch->colUsed |= ((Bitmask)1)<<n;
}
/* Clean up and return
*/
sqlite3ExprDelete(db, pExpr->pLeft);
pExpr->pLeft = 0;
sqlite3ExprDelete(db, pExpr->pRight);
pExpr->pRight = 0;
pExpr->op = (isTrigger ? TK_TRIGGER : TK_COLUMN);
lookupname_end:
if( cnt==1 ){
assert( pNC!=0 );
sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
/* Increment the nRef value on all name contexts from TopNC up to
** the point where the name matched. */
for(;;){
assert( pTopNC!=0 );
pTopNC->nRef++;
if( pTopNC==pNC ) break;
pTopNC = pTopNC->pNext;
}
return WRC_Prune;
} else {
return WRC_Abort;
}
}
/*
** Allocate and return a pointer to an expression to load the column iCol
** from datasource iSrc in SrcList pSrc.
*/
Expr *sqlite3CreateColumnExpr(sqlite3 *db, SrcList *pSrc, int iSrc, int iCol){
Expr *p = sqlite3ExprAlloc(db, TK_COLUMN, 0, 0);
if( p ){
struct SrcList_item *pItem = &pSrc->a[iSrc];
p->pTab = pItem->pTab;
p->iTable = pItem->iCursor;
if( p->pTab->iPKey==iCol ){
p->iColumn = -1;
}else{
p->iColumn = (ynVar)iCol;
testcase( iCol==BMS );
testcase( iCol==BMS-1 );
pItem->colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
}
ExprSetProperty(p, EP_Resolved);
}
return p;
}
/*
** This routine is callback for sqlite3WalkExpr().
**
** Resolve symbolic names into TK_COLUMN operators for the current
** node in the expression tree. Return 0 to continue the search down
** the tree or 2 to abort the tree walk.
**
** This routine also does error checking and name resolution for
** function names. The operator for aggregate functions is changed
** to TK_AGG_FUNCTION.
*/
static int resolveExprStep(Walker *pWalker, Expr *pExpr){
NameContext *pNC;
Parse *pParse;
pNC = pWalker->u.pNC;
assert( pNC!=0 );
pParse = pNC->pParse;
assert( pParse==pWalker->pParse );
if( ExprHasAnyProperty(pExpr, EP_Resolved) ) return WRC_Prune;
ExprSetProperty(pExpr, EP_Resolved);
#ifndef NDEBUG
if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){
SrcList *pSrcList = pNC->pSrcList;
int i;
for(i=0; i<pNC->pSrcList->nSrc; i++){
assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
}
}
#endif
switch( pExpr->op ){
#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
/* The special operator TK_ROW means use the rowid for the first
** column in the FROM clause. This is used by the LIMIT and ORDER BY
** clause processing on UPDATE and DELETE statements.
*/
case TK_ROW: {
SrcList *pSrcList = pNC->pSrcList;
struct SrcList_item *pItem;
assert( pSrcList && pSrcList->nSrc==1 );
pItem = pSrcList->a;
pExpr->op = TK_COLUMN;
pExpr->pTab = pItem->pTab;
pExpr->iTable = pItem->iCursor;
pExpr->iColumn = -1;
pExpr->affinity = SQLITE_AFF_INTEGER;
break;
}
#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) */
/* A lone identifier is the name of a column.
*/
case TK_ID: {
return lookupName(pParse, 0, 0, pExpr->u.zToken, pNC, pExpr);
}
/* A table name and column name: ID.ID
** Or a database, table and column: ID.ID.ID
*/
case TK_DOT: {
const char *zColumn;
const char *zTable;
const char *zDb;
Expr *pRight;
/* if( pSrcList==0 ) break; */
pRight = pExpr->pRight;
if( pRight->op==TK_ID ){
zDb = 0;
zTable = pExpr->pLeft->u.zToken;
zColumn = pRight->u.zToken;
}else{
assert( pRight->op==TK_DOT );
zDb = pExpr->pLeft->u.zToken;
zTable = pRight->pLeft->u.zToken;
zColumn = pRight->pRight->u.zToken;
}
return lookupName(pParse, zDb, zTable, zColumn, pNC, pExpr);
}
/* Resolve function names
*/
case TK_CONST_FUNC:
case TK_FUNCTION: {
ExprList *pList = pExpr->x.pList; /* The argument list */
int n = pList ? pList->nExpr : 0; /* Number of arguments */
int no_such_func = 0; /* True if no such function exists */
int wrong_num_args = 0; /* True if wrong number of arguments */
int is_agg = 0; /* True if is an aggregate function */
int auth; /* Authorization to use the function */
int nId; /* Number of characters in function name */
const char *zId; /* The function name. */
FuncDef *pDef; /* Information about the function */
u8 enc = ENC(pParse->db); /* The database encoding */
testcase( pExpr->op==TK_CONST_FUNC );
assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
zId = pExpr->u.zToken;
nId = sqlite3Strlen30(zId);
pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
if( pDef==0 ){
pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
if( pDef==0 ){
no_such_func = 1;
}else{
wrong_num_args = 1;
}
}else{
is_agg = pDef->xFunc==0;
}
#ifndef SQLITE_OMIT_AUTHORIZATION
if( pDef ){
auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0, pDef->zName, 0);
if( auth!=SQLITE_OK ){
if( auth==SQLITE_DENY ){
sqlite3ErrorMsg(pParse, "not authorized to use function: %s",
pDef->zName);
pNC->nErr++;
}
pExpr->op = TK_NULL;
return WRC_Prune;
}
}
#endif
if( is_agg && !pNC->allowAgg ){
sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId);
pNC->nErr++;
is_agg = 0;
}else if( no_such_func ){
sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
pNC->nErr++;
}else if( wrong_num_args ){
sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
nId, zId);
pNC->nErr++;
}
if( is_agg ){
pExpr->op = TK_AGG_FUNCTION;
pNC->hasAgg = 1;
}
if( is_agg ) pNC->allowAgg = 0;
sqlite3WalkExprList(pWalker, pList);
if( is_agg ) pNC->allowAgg = 1;
/* FIX ME: Compute pExpr->affinity based on the expected return
** type of the function
*/
return WRC_Prune;
}
#ifndef SQLITE_OMIT_SUBQUERY
case TK_SELECT:
case TK_EXISTS: testcase( pExpr->op==TK_EXISTS );
#endif
case TK_IN: {
testcase( pExpr->op==TK_IN );
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
int nRef = pNC->nRef;
#ifndef SQLITE_OMIT_CHECK
if( pNC->isCheck ){
sqlite3ErrorMsg(pParse,"subqueries prohibited in CHECK constraints");
}
#endif
sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
assert( pNC->nRef>=nRef );
if( nRef!=pNC->nRef ){
ExprSetProperty(pExpr, EP_VarSelect);
}
}
break;
}
#ifndef SQLITE_OMIT_CHECK
case TK_VARIABLE: {
if( pNC->isCheck ){
sqlite3ErrorMsg(pParse,"parameters prohibited in CHECK constraints");
}
break;
}
#endif
}
return (pParse->nErr || pParse->db->mallocFailed) ? WRC_Abort : WRC_Continue;
}
/*
** pEList is a list of expressions which are really the result set of the
** a SELECT statement. pE is a term in an ORDER BY or GROUP BY clause.
** This routine checks to see if pE is a simple identifier which corresponds
** to the AS-name of one of the terms of the expression list. If it is,
** this routine return an integer between 1 and N where N is the number of
** elements in pEList, corresponding to the matching entry. If there is
** no match, or if pE is not a simple identifier, then this routine
** return 0.
**
** pEList has been resolved. pE has not.
*/
static int resolveAsName(
Parse *pParse, /* Parsing context for error messages */
ExprList *pEList, /* List of expressions to scan */
Expr *pE /* Expression we are trying to match */
){
int i; /* Loop counter */
UNUSED_PARAMETER(pParse);
if( pE->op==TK_ID ){
char *zCol = pE->u.zToken;
for(i=0; i<pEList->nExpr; i++){
char *zAs = pEList->a[i].zName;
if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
return i+1;
}
}
}
return 0;
}
/*
** pE is a pointer to an expression which is a single term in the
** ORDER BY of a compound SELECT. The expression has not been
** name resolved.
**
** At the point this routine is called, we already know that the
** ORDER BY term is not an integer index into the result set. That
** case is handled by the calling routine.
**
** Attempt to match pE against result set columns in the left-most
** SELECT statement. Return the index i of the matching column,
** as an indication to the caller that it should sort by the i-th column.
** The left-most column is 1. In other words, the value returned is the
** same integer value that would be used in the SQL statement to indicate
** the column.
**
** If there is no match, return 0. Return -1 if an error occurs.
*/
static int resolveOrderByTermToExprList(
Parse *pParse, /* Parsing context for error messages */
Select *pSelect, /* The SELECT statement with the ORDER BY clause */
Expr *pE /* The specific ORDER BY term */
){
int i; /* Loop counter */
ExprList *pEList; /* The columns of the result set */
NameContext nc; /* Name context for resolving pE */
sqlite3 *db; /* Database connection */
int rc; /* Return code from subprocedures */
u8 savedSuppErr; /* Saved value of db->suppressErr */
assert( sqlite3ExprIsInteger(pE, &i)==0 );
pEList = pSelect->pEList;
/* Resolve all names in the ORDER BY term expression
*/
memset(&nc, 0, sizeof(nc));
nc.pParse = pParse;
nc.pSrcList = pSelect->pSrc;
nc.pEList = pEList;
nc.allowAgg = 1;
nc.nErr = 0;
db = pParse->db;
savedSuppErr = db->suppressErr;
db->suppressErr = 1;
rc = sqlite3ResolveExprNames(&nc, pE);
db->suppressErr = savedSuppErr;
if( rc ) return 0;
/* Try to match the ORDER BY expression against an expression
** in the result set. Return an 1-based index of the matching
** result-set entry.
*/
for(i=0; i<pEList->nExpr; i++){
if( sqlite3ExprCompare(pEList->a[i].pExpr, pE)<2 ){
return i+1;
}
}
/* If no match, return 0. */
return 0;
}
/*
** Generate an ORDER BY or GROUP BY term out-of-range error.
*/
static void resolveOutOfRangeError(
Parse *pParse, /* The error context into which to write the error */
const char *zType, /* "ORDER" or "GROUP" */
int i, /* The index (1-based) of the term out of range */
int mx /* Largest permissible value of i */
){
sqlite3ErrorMsg(pParse,
"%r %s BY term out of range - should be "
"between 1 and %d", i, zType, mx);
}
/*
** Analyze the ORDER BY clause in a compound SELECT statement. Modify
** each term of the ORDER BY clause is a constant integer between 1
** and N where N is the number of columns in the compound SELECT.
**
** ORDER BY terms that are already an integer between 1 and N are
** unmodified. ORDER BY terms that are integers outside the range of
** 1 through N generate an error. ORDER BY terms that are expressions
** are matched against result set expressions of compound SELECT
** beginning with the left-most SELECT and working toward the right.
** At the first match, the ORDER BY expression is transformed into
** the integer column number.
**
** Return the number of errors seen.
*/
static int resolveCompoundOrderBy(
Parse *pParse, /* Parsing context. Leave error messages here */
Select *pSelect /* The SELECT statement containing the ORDER BY */
){
int i;
ExprList *pOrderBy;
ExprList *pEList;
sqlite3 *db;
int moreToDo = 1;
pOrderBy = pSelect->pOrderBy;
if( pOrderBy==0 ) return 0;
db = pParse->db;
#if SQLITE_MAX_COLUMN
if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause");
return 1;
}
#endif
for(i=0; i<pOrderBy->nExpr; i++){
pOrderBy->a[i].done = 0;
}
pSelect->pNext = 0;
while( pSelect->pPrior ){
pSelect->pPrior->pNext = pSelect;
pSelect = pSelect->pPrior;
}
while( pSelect && moreToDo ){
struct ExprList_item *pItem;
moreToDo = 0;
pEList = pSelect->pEList;
assert( pEList!=0 );
for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
int iCol = -1;
Expr *pE, *pDup;
if( pItem->done ) continue;
pE = pItem->pExpr;
if( sqlite3ExprIsInteger(pE, &iCol) ){
if( iCol<=0 || iCol>pEList->nExpr ){
resolveOutOfRangeError(pParse, "ORDER", i+1, pEList->nExpr);
return 1;
}
}else{
iCol = resolveAsName(pParse, pEList, pE);
if( iCol==0 ){
pDup = sqlite3ExprDup(db, pE, 0);
if( !db->mallocFailed ){
assert(pDup);
iCol = resolveOrderByTermToExprList(pParse, pSelect, pDup);
}
sqlite3ExprDelete(db, pDup);
}
}
if( iCol>0 ){
CollSeq *pColl = pE->pColl;
int flags = pE->flags & EP_ExpCollate;
sqlite3ExprDelete(db, pE);
pItem->pExpr = pE = sqlite3Expr(db, TK_INTEGER, 0);
if( pE==0 ) return 1;
pE->pColl = pColl;
pE->flags |= EP_IntValue | flags;
pE->u.iValue = iCol;
pItem->iCol = (u16)iCol;
pItem->done = 1;
}else{
moreToDo = 1;
}
}
pSelect = pSelect->pNext;
}
for(i=0; i<pOrderBy->nExpr; i++){
if( pOrderBy->a[i].done==0 ){
sqlite3ErrorMsg(pParse, "%r ORDER BY term does not match any "
"column in the result set", i+1);
return 1;
}
}
return 0;
}
/*
** Check every term in the ORDER BY or GROUP BY clause pOrderBy of
** the SELECT statement pSelect. If any term is reference to a
** result set expression (as determined by the ExprList.a.iCol field)
** then convert that term into a copy of the corresponding result set
** column.
**
** If any errors are detected, add an error message to pParse and
** return non-zero. Return zero if no errors are seen.
*/
int sqlite3ResolveOrderGroupBy(
Parse *pParse, /* Parsing context. Leave error messages here */
Select *pSelect, /* The SELECT statement containing the clause */
ExprList *pOrderBy, /* The ORDER BY or GROUP BY clause to be processed */
const char *zType /* "ORDER" or "GROUP" */
){
int i;
sqlite3 *db = pParse->db;
ExprList *pEList;
struct ExprList_item *pItem;
if( pOrderBy==0 || pParse->db->mallocFailed ) return 0;
#if SQLITE_MAX_COLUMN
if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
return 1;
}
#endif
pEList = pSelect->pEList;
assert( pEList!=0 ); /* sqlite3SelectNew() guarantees this */
for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
if( pItem->iCol ){
if( pItem->iCol>pEList->nExpr ){
resolveOutOfRangeError(pParse, zType, i+1, pEList->nExpr);
return 1;
}
resolveAlias(pParse, pEList, pItem->iCol-1, pItem->pExpr, zType);
}
}
return 0;
}
/*
** pOrderBy is an ORDER BY or GROUP BY clause in SELECT statement pSelect.
** The Name context of the SELECT statement is pNC. zType is either
** "ORDER" or "GROUP" depending on which type of clause pOrderBy is.
**
** This routine resolves each term of the clause into an expression.
** If the order-by term is an integer I between 1 and N (where N is the
** number of columns in the result set of the SELECT) then the expression
** in the resolution is a copy of the I-th result-set expression. If
** the order-by term is an identify that corresponds to the AS-name of
** a result-set expression, then the term resolves to a copy of the
** result-set expression. Otherwise, the expression is resolved in
** the usual way - using sqlite3ResolveExprNames().
**
** This routine returns the number of errors. If errors occur, then
** an appropriate error message might be left in pParse. (OOM errors
** excepted.)
*/
static int resolveOrderGroupBy(
NameContext *pNC, /* The name context of the SELECT statement */
Select *pSelect, /* The SELECT statement holding pOrderBy */
ExprList *pOrderBy, /* An ORDER BY or GROUP BY clause to resolve */
const char *zType /* Either "ORDER" or "GROUP", as appropriate */
){
int i; /* Loop counter */
int iCol; /* Column number */
struct ExprList_item *pItem; /* A term of the ORDER BY clause */
Parse *pParse; /* Parsing context */
int nResult; /* Number of terms in the result set */
if( pOrderBy==0 ) return 0;
nResult = pSelect->pEList->nExpr;
pParse = pNC->pParse;
for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
Expr *pE = pItem->pExpr;
iCol = resolveAsName(pParse, pSelect->pEList, pE);
if( iCol>0 ){
/* If an AS-name match is found, mark this ORDER BY column as being
** a copy of the iCol-th result-set column. The subsequent call to
** sqlite3ResolveOrderGroupBy() will convert the expression to a
** copy of the iCol-th result-set expression. */
pItem->iCol = (u16)iCol;
continue;
}
if( sqlite3ExprIsInteger(pE, &iCol) ){
/* The ORDER BY term is an integer constant. Again, set the column
** number so that sqlite3ResolveOrderGroupBy() will convert the
** order-by term to a copy of the result-set expression */
if( iCol<1 ){
resolveOutOfRangeError(pParse, zType, i+1, nResult);
return 1;
}
pItem->iCol = (u16)iCol;
continue;
}
/* Otherwise, treat the ORDER BY term as an ordinary expression */
pItem->iCol = 0;
if( sqlite3ResolveExprNames(pNC, pE) ){
return 1;
}
}
return sqlite3ResolveOrderGroupBy(pParse, pSelect, pOrderBy, zType);
}
/*
** Resolve names in the SELECT statement p and all of its descendents.
*/
static int resolveSelectStep(Walker *pWalker, Select *p){
NameContext *pOuterNC; /* Context that contains this SELECT */
NameContext sNC; /* Name context of this SELECT */
int isCompound; /* True if p is a compound select */
int nCompound; /* Number of compound terms processed so far */
Parse *pParse; /* Parsing context */
ExprList *pEList; /* Result set expression list */
int i; /* Loop counter */
ExprList *pGroupBy; /* The GROUP BY clause */
Select *pLeftmost; /* Left-most of SELECT of a compound */
sqlite3 *db; /* Database connection */
assert( p!=0 );
if( p->selFlags & SF_Resolved ){
return WRC_Prune;
}
pOuterNC = pWalker->u.pNC;
pParse = pWalker->pParse;
db = pParse->db;
/* Normally sqlite3SelectExpand() will be called first and will have
** already expanded this SELECT. However, if this is a subquery within
** an expression, sqlite3ResolveExprNames() will be called without a
** prior call to sqlite3SelectExpand(). When that happens, let
** sqlite3SelectPrep() do all of the processing for this SELECT.
** sqlite3SelectPrep() will invoke both sqlite3SelectExpand() and
** this routine in the correct order.
*/
if( (p->selFlags & SF_Expanded)==0 ){
sqlite3SelectPrep(pParse, p, pOuterNC);
return (pParse->nErr || db->mallocFailed) ? WRC_Abort : WRC_Prune;
}
isCompound = p->pPrior!=0;
nCompound = 0;
pLeftmost = p;
while( p ){
assert( (p->selFlags & SF_Expanded)!=0 );
assert( (p->selFlags & SF_Resolved)==0 );
p->selFlags |= SF_Resolved;
/* Resolve the expressions in the LIMIT and OFFSET clauses. These
** are not allowed to refer to any names, so pass an empty NameContext.
*/
memset(&sNC, 0, sizeof(sNC));
sNC.pParse = pParse;
if( sqlite3ResolveExprNames(&sNC, p->pLimit) ||
sqlite3ResolveExprNames(&sNC, p->pOffset) ){
return WRC_Abort;
}
/* Set up the local name-context to pass to sqlite3ResolveExprNames() to
** resolve the result-set expression list.
*/
sNC.allowAgg = 1;
sNC.pSrcList = p->pSrc;
sNC.pNext = pOuterNC;
/* Resolve names in the result set. */
pEList = p->pEList;
assert( pEList!=0 );
for(i=0; i<pEList->nExpr; i++){
Expr *pX = pEList->a[i].pExpr;
if( sqlite3ResolveExprNames(&sNC, pX) ){
return WRC_Abort;
}
}
/* Recursively resolve names in all subqueries
*/
for(i=0; i<p->pSrc->nSrc; i++){
struct SrcList_item *pItem = &p->pSrc->a[i];
if( pItem->pSelect ){
const char *zSavedContext = pParse->zAuthContext;
if( pItem->zName ) pParse->zAuthContext = pItem->zName;
sqlite3ResolveSelectNames(pParse, pItem->pSelect, pOuterNC);
pParse->zAuthContext = zSavedContext;
if( pParse->nErr || db->mallocFailed ) return WRC_Abort;
}
}
/* If there are no aggregate functions in the result-set, and no GROUP BY
** expression, do not allow aggregates in any of the other expressions.
*/
assert( (p->selFlags & SF_Aggregate)==0 );
pGroupBy = p->pGroupBy;
if( pGroupBy || sNC.hasAgg ){
p->selFlags |= SF_Aggregate;
}else{
sNC.allowAgg = 0;
}
/* If a HAVING clause is present, then there must be a GROUP BY clause.
*/
if( p->pHaving && !pGroupBy ){
sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
return WRC_Abort;
}
/* Add the expression list to the name-context before parsing the
** other expressions in the SELECT statement. This is so that
** expressions in the WHERE clause (etc.) can refer to expressions by
** aliases in the result set.
**
** Minor point: If this is the case, then the expression will be
** re-evaluated for each reference to it.
*/
sNC.pEList = p->pEList;
if( sqlite3ResolveExprNames(&sNC, p->pWhere) ||
sqlite3ResolveExprNames(&sNC, p->pHaving)
){
return WRC_Abort;
}
/* The ORDER BY and GROUP BY clauses may not refer to terms in
** outer queries
*/
sNC.pNext = 0;
sNC.allowAgg = 1;
/* Process the ORDER BY clause for singleton SELECT statements.
** The ORDER BY clause for compounds SELECT statements is handled
** below, after all of the result-sets for all of the elements of
** the compound have been resolved.
*/
if( !isCompound && resolveOrderGroupBy(&sNC, p, p->pOrderBy, "ORDER") ){
return WRC_Abort;
}
if( db->mallocFailed ){
return WRC_Abort;
}
/* Resolve the GROUP BY clause. At the same time, make sure
** the GROUP BY clause does not contain aggregate functions.
*/
if( pGroupBy ){
struct ExprList_item *pItem;
if( resolveOrderGroupBy(&sNC, p, pGroupBy, "GROUP") || db->mallocFailed ){
return WRC_Abort;
}
for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
"the GROUP BY clause");
return WRC_Abort;
}
}
}
/* Advance to the next term of the compound
*/
p = p->pPrior;
nCompound++;
}
/* Resolve the ORDER BY on a compound SELECT after all terms of
** the compound have been resolved.
*/
if( isCompound && resolveCompoundOrderBy(pParse, pLeftmost) ){
return WRC_Abort;
}
return WRC_Prune;
}
/*
** This routine walks an expression tree and resolves references to
** table columns and result-set columns. At the same time, do error
** checking on function usage and set a flag if any aggregate functions
** are seen.
**
** To resolve table columns references we look for nodes (or subtrees) of the
** form X.Y.Z or Y.Z or just Z where
**
** X: The name of a database. Ex: "main" or "temp" or
** the symbolic name assigned to an ATTACH-ed database.
**
** Y: The name of a table in a FROM clause. Or in a trigger
** one of the special names "old" or "new".
**
** Z: The name of a column in table Y.
**
** The node at the root of the subtree is modified as follows:
**
** Expr.op Changed to TK_COLUMN
** Expr.pTab Points to the Table object for X.Y
** Expr.iColumn The column index in X.Y. -1 for the rowid.
** Expr.iTable The VDBE cursor number for X.Y
**
**
** To resolve result-set references, look for expression nodes of the
** form Z (with no X and Y prefix) where the Z matches the right-hand
** size of an AS clause in the result-set of a SELECT. The Z expression
** is replaced by a copy of the left-hand side of the result-set expression.
** Table-name and function resolution occurs on the substituted expression
** tree. For example, in:
**
** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY x;
**
** The "x" term of the order by is replaced by "a+b" to render:
**
** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY a+b;
**
** Function calls are checked to make sure that the function is
** defined and that the correct number of arguments are specified.
** If the function is an aggregate function, then the pNC->hasAgg is
** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION.
** If an expression contains aggregate functions then the EP_Agg
** property on the expression is set.
**
** An error message is left in pParse if anything is amiss. The number
** if errors is returned.
*/
int sqlite3ResolveExprNames(
NameContext *pNC, /* Namespace to resolve expressions in. */
Expr *pExpr /* The expression to be analyzed. */
){
int savedHasAgg;
Walker w;
if( pExpr==0 ) return 0;
#if SQLITE_MAX_EXPR_DEPTH>0
{
Parse *pParse = pNC->pParse;
if( sqlite3ExprCheckHeight(pParse, pExpr->nHeight+pNC->pParse->nHeight) ){
return 1;
}
pParse->nHeight += pExpr->nHeight;
}
#endif
savedHasAgg = pNC->hasAgg;
pNC->hasAgg = 0;
w.xExprCallback = resolveExprStep;
w.xSelectCallback = resolveSelectStep;
w.pParse = pNC->pParse;
w.u.pNC = pNC;
sqlite3WalkExpr(&w, pExpr);
#if SQLITE_MAX_EXPR_DEPTH>0
pNC->pParse->nHeight -= pExpr->nHeight;
#endif
if( pNC->nErr>0 || w.pParse->nErr>0 ){
ExprSetProperty(pExpr, EP_Error);
}
if( pNC->hasAgg ){
ExprSetProperty(pExpr, EP_Agg);
}else if( savedHasAgg ){
pNC->hasAgg = 1;
}
return ExprHasProperty(pExpr, EP_Error);
}
/*
** Resolve all names in all expressions of a SELECT and in all
** decendents of the SELECT, including compounds off of p->pPrior,
** subqueries in expressions, and subqueries used as FROM clause
** terms.
**
** See sqlite3ResolveExprNames() for a description of the kinds of
** transformations that occur.
**
** All SELECT statements should have been expanded using
** sqlite3SelectExpand() prior to invoking this routine.
*/
void sqlite3ResolveSelectNames(
Parse *pParse, /* The parser context */
Select *p, /* The SELECT statement being coded. */
NameContext *pOuterNC /* Name context for parent SELECT statement */
){
Walker w;
assert( p!=0 );
w.xExprCallback = resolveExprStep;
w.xSelectCallback = resolveSelectStep;
w.pParse = pParse;
w.u.pNC = pOuterNC;
sqlite3WalkSelect(&w, p);
}