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 1.222 2005/08/30 00:54:02 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

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

** sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
** for additional information.
**
** This routine analyzes the aggregate function at pExpr.
*/
static int analyzeAggregate(void *pArg, Expr *pExpr){
  int i;
  AggExpr *pAgg;
  NameContext *pNC = (NameContext *)pArg;
  Parse *pParse = pNC->pParse;
  SrcList *pSrcList = pNC->pSrcList;
  Expr *pAggExpr;

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

** the number of errors.
*/
int sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
  int nErr = pNC->pParse->nErr;
  walkExprTree(pExpr, analyzeAggregate, pNC);
  return pNC->pParse->nErr - nErr;
}

/*
** Call sqlite3ExprAnalyzeAggregates() for every expression in an
** expression list.  Return the number of errors.
**
** If an error is found, the analysis is cut short.
*/
int sqlite3ExprAnalyzeAggList(NameContext *pNC, ExprList *pList){
  struct ExprList_item *pItem;
  int i;
  int nErr = 0;
  if( pList ){
    for(pItem=pList->a, i=0; nErr==0 && i<pList->nExpr; i++, pItem++){
      nErr += sqlite3ExprAnalyzeAggregates(pNC, pItem->pExpr);
    }
  }
  return nErr;
}

**    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 1.256 2005/08/30 00:54:03 drh Exp $
*/
#include "sqliteInt.h"


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

  }
#endif

  /* If there is an ORDER BY clause, resolve any collation sequences
  ** names that have been explicitly specified.
  */
  if( pOrderBy ){
    struct ExprList_item *pTerm;
    for(i=0, pTerm=pOrderBy->a; i<pOrderBy->nExpr; i++, pTerm++){
      if( pTerm->zName ){

        pTerm->pExpr->pColl = sqlite3LocateCollSeq(pParse, pTerm->zName, -1);
      }
    }
    if( pParse->nErr ){
      goto select_end;
    }
  }

    NameContext sNC;
    memset(&sNC, 0, sizeof(sNC));
    sNC.pParse = pParse;
    sNC.pSrcList = pTabList;

    assert( pParse->nAgg==0 );
    isAgg = 1;

    if( sqlite3ExprAnalyzeAggList(&sNC, pEList) ){
      goto select_end;
    }



    if( sqlite3ExprAnalyzeAggList(&sNC, pGroupBy) ){
      goto select_end;


    }
    if( pHaving && sqlite3ExprAnalyzeAggregates(&sNC, pHaving) ){
      goto select_end;
    }


    if( sqlite3ExprAnalyzeAggList(&sNC, pOrderBy) ){
      goto select_end;


    }
  }

  /* Reset the aggregator
  */
  if( isAgg ){
    int addr = sqlite3VdbeAddOp(v, OP_AggReset, (pGroupBy?0:1), pParse->nAgg);

/*
** 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 1.406 2005/08/30 00:54:03 drh 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

  int nAlloc;            /* Number of entries allocated below */
  struct ExprList_item {
    Expr *pExpr;           /* The list of expressions */
    char *zName;           /* Token associated with this expression */
    u8 sortOrder;          /* 1 for DESC or 0 for ASC */
    u8 isAgg;              /* True if this is an aggregate like count(*) */
    u8 done;               /* A flag to indicate when processing is finished */
    u8 orderByDup[2];      /* Corresponding term in OrderBy/GroupBy clause */
  } *a;                  /* One entry for each expression */
};

/*
** An instance of this structure can hold a simple list of identifiers,
** such as the list "a,b,c" in the following statements:
**

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*);
int sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
Vdbe *sqlite3GetVdbe(Parse*);
void sqlite3Randomness(int, void*);
void sqlite3RollbackAll(sqlite3*);
void sqlite3CodeVerifySchema(Parse*, int);
void sqlite3BeginTransaction(Parse*, int);
void sqlite3CommitTransaction(Parse*);
void sqlite3RollbackTransaction(Parse*);