SQLite

**    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 analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.193 2005/02/08 07:50:41 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**

  if( pNew==0 ){
    /* When malloc fails, we leak memory from pLeft and pRight */
    return 0;
  }
  pNew->op = op;
  pNew->pLeft = pLeft;
  pNew->pRight = pRight;
  pNew->iAgg = -1;
  if( pToken ){
    assert( pToken->dyn==0 );
    pNew->span = pNew->token = *pToken;
  }else if( pLeft && pRight ){
    sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span);
  }
  return pNew;

** 0 means continue walking the tree.  1 means do not walk children
** of the current node but continue with siblings.  2 means abandon
** the tree walk completely.
**
** The return value from this routine is 1 to abandon the tree walk
** and 0 to continue.
*/
static int walkExprList(ExprList *, int (*)(void *, Expr*), void *);
static int walkExprTree(Expr *pExpr, int (*xFunc)(void*,Expr*), void *pArg){

  int rc;
  if( pExpr==0 ) return 0;
  rc = (*xFunc)(pArg, pExpr);
  if( rc==0 ){
    if( walkExprTree(pExpr->pLeft, xFunc, pArg) ) return 1;
    if( walkExprTree(pExpr->pRight, xFunc, pArg) ) return 1;
    if( walkExprList(pExpr->pList, xFunc, pArg) ) return 1;
  }
  return rc>1;
}

/*
** Call walkExprTree() for every expression in list p.
*/
static int walkExprList(ExprList *p, int (*xFunc)(void *, Expr*), void *pArg){
  int i;
  struct ExprList_item *pItem;
  if( !p ) return 0;
  for(i=p->nExpr, pItem=p->a; i>0; i--, pItem++){
    if( walkExprTree(pItem->pExpr, xFunc, pArg) ) return 1;
  }
  return 0;
}

/*
** Call walkExprTree() for every expression in Select p, not including
** expressions that are part of sub-selects in any FROM clause or the LIMIT
** or OFFSET expressions..
*/
static int walkSelectExpr(Select *p, int (*xFunc)(void *, Expr*), void *pArg){
  walkExprList(p->pEList, xFunc, pArg);
  walkExprTree(p->pWhere, xFunc, pArg);
  walkExprList(p->pGroupBy, xFunc, pArg);
  walkExprTree(p->pHaving, xFunc, pArg);
  walkExprList(p->pOrderBy, xFunc, pArg);
  return 0;
}


/*
** This routine is designed as an xFunc for walkExprTree().
**
** pArg is really a pointer to an integer.  If we can tell by looking
** at pExpr that the expression that contains pExpr is not a constant
** expression, then set *pArg to 0 and return 2 to abandon the tree walk.

  if( pExpr==0 ){
    sqlite3VdbeAddOp(v, OP_String8, 0, 0);  /* Empty expression evals to NULL */
    return;
  }
  op = pExpr->op;
  switch( op ){
    case TK_COLUMN: {
      if( !pParse->fillAgg && pExpr->iAgg>=0 ){
        sqlite3VdbeAddOp(v, OP_AggGet, pExpr->iAggCtx, pExpr->iAgg);
      }else if( pExpr->iColumn>=0 ){
        sqlite3VdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
#ifndef NDEBUG
        if( pExpr->span.z && pExpr->span.n>0 && pExpr->span.n<100 ){
          VdbeComment((v, "# %T", &pExpr->span));
        }
#endif

** for additional information.
**
** This routine analyzes the aggregate function at pExpr.
*/
static int analyzeAggregate(void *pArg, Expr *pExpr){
  int i;
  AggExpr *aAgg;
  NameContext *pNC = (NameContext *)pArg;
  Parse *pParse = pNC->pParse;
  SrcList *pSrcList = pNC->pSrcList;

  switch( pExpr->op ){
    case TK_COLUMN: {
      for(i=0; pSrcList && i<pSrcList->nSrc; i++){
        if( pExpr->iTable==pSrcList->a[i].iCursor ){
          aAgg = pParse->aAgg;
          for(i=0; i<pParse->nAgg; i++){
            if( aAgg[i].isAgg ) continue;
            if( aAgg[i].pExpr->iTable==pExpr->iTable
             && aAgg[i].pExpr->iColumn==pExpr->iColumn ){
              break;
            }
          }
          if( i>=pParse->nAgg ){
            i = appendAggInfo(pParse);
            if( i<0 ) return 1;
            pParse->aAgg[i].isAgg = 0;
            pParse->aAgg[i].pExpr = pExpr;
          }
          pExpr->iAgg = i;
          pExpr->iAggCtx = pNC->nDepth;
          return 1;
        }
      }
      return 1;
    }
    case TK_AGG_FUNCTION: {
      if( pNC->nDepth==0 ){
        aAgg = pParse->aAgg;
        for(i=0; i<pParse->nAgg; i++){
          if( !aAgg[i].isAgg ) continue;
          if( sqlite3ExprCompare(aAgg[i].pExpr, pExpr) ){
            break;
          }
        }
        if( i>=pParse->nAgg ){
          u8 enc = pParse->db->enc;
          i = appendAggInfo(pParse);
          if( i<0 ) return 1;
          pParse->aAgg[i].isAgg = 1;
          pParse->aAgg[i].pExpr = pExpr;
          pParse->aAgg[i].pFunc = sqlite3FindFunction(pParse->db,
               pExpr->token.z, pExpr->token.n,
               pExpr->pList ? pExpr->pList->nExpr : 0, enc, 0);
        }
        pExpr->iAgg = i;
        return 1;
      }
    }
  }
  if( pExpr->pSelect ){
    pNC->nDepth++;
    walkSelectExpr(pExpr->pSelect, analyzeAggregate, pNC);
    pNC->nDepth--;
  }
  return 0;
}

/*
** Analyze the given expression looking for aggregate functions and
** for variables that need to be added to the pParse->aAgg[] array.
** Make additional entries to the pParse->aAgg[] array as necessary.
**
** This routine should only be called after the expression has been
** analyzed by sqlite3ExprResolveNames().
**
** If errors are seen, leave an error message in zErrMsg and return
** the number of errors.
*/
int sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
  int nErr = pNC->pParse->nErr;
  walkExprTree(pExpr, analyzeAggregate, pNC);
  return pNC->pParse->nErr - nErr;
}

/*
** Locate a user function given a name, a number of arguments and a flag
** indicating whether the function prefers UTF-16 over UTF-8.  Return a
** pointer to the FuncDef structure that defines that function, or return
** NULL if the function does not exist.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.240 2005/02/08 07:50:41 danielk1977 Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.

        iCol = j;
      }
    }
    if( iCol>=0 ){
      pE->op = TK_COLUMN;
      pE->iColumn = iCol;
      pE->iTable = iTable;
      pE->iAgg = -1;
      pOrderBy->a[i].done = 1;
    }
    if( iCol<0 && mustComplete ){
      sqlite3ErrorMsg(pParse,
        "ORDER BY term number %d does not match any result column", i+1);
      nErr++;
      break;

  }

  /* The flattened query is distinct if either the inner or the
  ** outer query is distinct. 
  */
  p->isDistinct = p->isDistinct || pSub->isDistinct;

  /*
  ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
  */
  if( pSub->pLimit ){
    p->pLimit = pSub->pLimit;
    pSub->pLimit = 0;
  }

  /* Finially, delete what is left of the subquery and return
  ** success.

/*
** An instance of the following struct is used by sqlite3Select()
** to save aggregate related information from the Parse object
** at the start of each call and to restore it at the end. See
** saveAggregateInfo() and restoreAggregateInfo().
*/ 
struct AggregateInfo {

  int nAgg;
  AggExpr *aAgg;
};
typedef struct AggregateInfo AggregateInfo;

/* 
** Copy aggregate related information from the Parse structure
** into the AggregateInfo structure. Zero the aggregate related
** values in the Parse struct.
*/
static void saveAggregateInfo(Parse *pParse, AggregateInfo *pInfo){
  pInfo->aAgg = pParse->aAgg;
  pInfo->nAgg = pParse->nAgg;

  pParse->aAgg = 0;
  pParse->nAgg = 0;

}

/*
** Copy aggregate related information from the AggregateInfo struct
** back into the Parse structure. The aggregate related information
** currently stored in the Parse structure is deleted.
*/
static void restoreAggregateInfo(Parse *pParse, AggregateInfo *pInfo){
  sqliteFree(pParse->aAgg);
  pParse->aAgg = pInfo->aAgg;
  pParse->nAgg = pInfo->nAgg;

}
  
/*
** Generate code for the given SELECT statement.
**
** The results are distributed in various ways depending on the
** value of eDest and iParm.

    sqlite3VdbeAddOp(v, OP_OpenTemp, iParm, 0);
    sqlite3VdbeAddOp(v, OP_SetNumColumns, iParm, pEList->nExpr);
  }

  /* Do an analysis of aggregate expressions.
  */
  if( isAgg || pGroupBy ){
    NameContext sNC;
    memset(&sNC, 0, sizeof(sNC));
    sNC.pParse = pParse;
    sNC.pSrcList = pTabList;

    assert( pParse->nAgg==0 );
    isAgg = 1;
    for(i=0; i<pEList->nExpr; i++){
      if( sqlite3ExprAnalyzeAggregates(&sNC, pEList->a[i].pExpr) ){
        goto select_end;
      }
    }
    if( pGroupBy ){
      for(i=0; i<pGroupBy->nExpr; i++){
        if( sqlite3ExprAnalyzeAggregates(&sNC, pGroupBy->a[i].pExpr) ){
          goto select_end;
        }
      }
    }
    if( pHaving && sqlite3ExprAnalyzeAggregates(&sNC, pHaving) ){
      goto select_end;
    }
    if( pOrderBy ){
      for(i=0; i<pOrderBy->nExpr; i++){
        if( sqlite3ExprAnalyzeAggregates(&sNC, pOrderBy->a[i].pExpr) ){
          goto select_end;
        }
      }
    }
  }

  /* Reset the aggregator

  }

  /* If we are dealing with aggregates, then do the special aggregate
  ** processing.  
  */
  else{
    AggExpr *pAgg;
    int lbl1 = 0;
    pParse->fillAgg = 1;
    if( pGroupBy ){

      for(i=0; i<pGroupBy->nExpr; i++){
        sqlite3ExprCode(pParse, pGroupBy->a[i].pExpr);
      }
      /* No affinity string is attached to the following OP_MakeRecord 
      ** because we do not need to do any coercion of datatypes. */
      sqlite3VdbeAddOp(v, OP_MakeRecord, pGroupBy->nExpr, 0);
      lbl1 = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp(v, OP_AggFocus, 0, lbl1);
    }
    for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){
      if( pAgg->isAgg ) continue;
      sqlite3ExprCode(pParse, pAgg->pExpr);
      sqlite3VdbeAddOp(v, OP_AggSet, 0, i);
    }
    pParse->fillAgg = 0;
    if( lbl1<0 ){
      sqlite3VdbeResolveLabel(v, lbl1);
    }
    for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){
      Expr *pE;
      int nExpr;
      FuncDef *pDef;
      if( !pAgg->isAgg ) continue;

  /* If we are processing aggregates, we need to set up a second loop
  ** over all of the aggregate values and process them.
  */
  if( isAgg ){
    int endagg = sqlite3VdbeMakeLabel(v);
    int startagg;
    startagg = sqlite3VdbeAddOp(v, OP_AggNext, 0, endagg);

    if( pHaving ){
      sqlite3ExprIfFalse(pParse, pHaving, startagg, 1);
    }
    if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
                    iParm, startagg, endagg, aff) ){
      goto select_end;
    }
    sqlite3VdbeAddOp(v, OP_Goto, 0, startagg);
    sqlite3VdbeResolveLabel(v, endagg);
    sqlite3VdbeAddOp(v, OP_Noop, 0, 0);

  }

  /* If there is an ORDER BY clause, then we need to sort the results
  ** and send them to the callback one by one.
  */
  if( pOrderBy ){
    generateSortTail(pParse, p, v, pEList->nExpr, eDest, iParm);

/*
** 2001 September 15
**
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.369 2005/02/08 07:50:42 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks

  Expr *pLeft, *pRight;  /* Left and right subnodes */
  ExprList *pList;       /* A list of expressions used as function arguments
                         ** or in "<expr> IN (<expr-list)" */
  Token token;           /* An operand token */
  Token span;            /* Complete text of the expression */
  int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
                         ** iColumn-th field of the iTable-th table. */
  int iAgg;              /* When op==TK_COLUMN and pParse->fillAgg==FALSE, pull
                         ** result from the iAgg-th element of the aggregator */
  int iAggCtx;           /* The value to pass as P1 of OP_AggGet. */
  Select *pSelect;       /* When the expression is a sub-select.  Also the
                         ** right side of "<expr> IN (<select>)" */
};

/*
** The following are the meanings of bits in the Expr.flags field.
*/

  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  u32 cookieMask;      /* Bitmask of schema verified databases */
  int cookieValue[MAX_ATTACHED+2];  /* Values of cookies to verify */
  int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
  u32 writeMask;       /* Start a write transaction on these databases */

  u8 fillAgg;          /* If true, ignore the Expr.iAgg field. Normally false */

  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */
  int nVarExpr;        /* Number of used slots in apVarExpr[] */
  int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */

void sqlite3Vacuum(Parse*, Token*);
int sqlite3RunVacuum(char**, sqlite3*);
char *sqlite3NameFromToken(Token*);
int sqlite3ExprCheck(Parse*, Expr*, int, int*);
int sqlite3ExprCompare(Expr*, Expr*);
int sqliteFuncId(Token*);
int sqlite3ExprResolveNames(NameContext *, Expr *);
int sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
Vdbe *sqlite3GetVdbe(Parse*);
void sqlite3Randomness(int, void*);
void sqlite3RollbackAll(sqlite3*);
void sqlite3CodeVerifySchema(Parse*, int);
void sqlite3BeginTransaction(Parse*, int);
void sqlite3CommitTransaction(Parse*);
void sqlite3RollbackTransaction(Parse*);

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.454 2005/02/08 07:50:42 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  if( pFocus==0 ) goto no_mem;
  assert( i>=0 && i<p->pAgg->nMem );
  rc = sqlite3VdbeMemMove(&pFocus->aMem[i], pTos);
  pTos--;
  break;
}

/* Opcode: AggGet P1 P2 *
**
** Push a new entry onto the stack which is a copy of the P2-th field
** of the current aggregate.  Strings are not duplicated so
** string values will be ephemeral.
**
** If P1 is zero, then the value is pulled out of the current aggregate
** in the current aggregate context. If P1 is greater than zero, then
** the value is taken from the P1th outer aggregate context. (i.e. if
** P1==1 then read from the aggregate context that will be restored
** by the next OP_AggContextPop opcode).
*/
case OP_AggGet: {
  AggElem *pFocus;
  int i = pOp->p2;
  Agg *pAgg = &p->pAgg[-pOp->p1];
  assert( pAgg>=p->apAgg );
  pFocus = pAgg->pCurrent;
  if( pFocus==0 ){
    int res;
    if( sqlite3_malloc_failed ) goto no_mem;
    rc = sqlite3BtreeFirst(pAgg->pCsr, &res);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    if( res!=0 ){
      rc = AggInsert(pAgg, "", 1);
      pFocus = pAgg->pCurrent;
    }else{
      rc = sqlite3BtreeData(pAgg->pCsr, 0, 4, (char *)&pFocus);
    }
  }
  assert( i>=0 && i<pAgg->nMem );
  pTos++;
  sqlite3VdbeMemShallowCopy(pTos, &pFocus->aMem[i], MEM_Ephem);
  if( pTos->flags&MEM_Str ){
    sqlite3VdbeChangeEncoding(pTos, db->enc);
  }
  break;
}

# 2005 January 19
#
# 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 implements regression tests for SQLite library.  The
# focus of this script is testing correlated subqueries
#
# $Id: subquery.test,v 1.5 2005/02/08 07:50:42 danielk1977 Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable !subquery {
  finish_test

    CREATE TABLE t1(a,b);
    INSERT INTO t1 VALUES(1,2);
  }
  execsql {
    SELECT (SELECT t1.a) FROM t1;
  }
} {1}

# Test Cases subquery-3.3.* test correlated subqueries where the
# parent query is an aggregate query. Ticket #1105 is an example
# of such a query.
#
do_test subquery-3.3.1 {
  execsql {
    SELECT a, (SELECT b) FROM t1 GROUP BY a;
  }
} {1 2}
do_test subquery-3.3.2 {
  catchsql {DROP TABLE t2}
  execsql {
    CREATE TABLE t2(c, d);
    INSERT INTO t2 VALUES(1, 'one');
    INSERT INTO t2 VALUES(2, 'two');
    SELECT a, (SELECT d FROM t2 WHERE a=c) FROM t1 GROUP BY a;
  }
} {1 one}
do_test subquery-3.3.3 {
  execsql {
    INSERT INTO t1 VALUES(2, 4);
    SELECT max(a), (SELECT d FROM t2 WHERE a=c) FROM t1;
  }
} {2 two}
do_test subquery-3.3.3 {
  execsql {
    SELECT a, (SELECT (SELECT d FROM t2 WHERE a=c)) FROM t1 GROUP BY a;
  }
} {1 one 2 two}

#------------------------------------------------------------------
# These tests - subquery-4.* - use the TCL statement cache to try 
# and expose bugs to do with re-using statements that have been 
# passed to sqlite3_reset().
#
# One problem was that VDBE memory cells were not being initialised