select.c

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  if( p==0 || p->pSrc==0 || db->mallocFailed ){
    return 1;
  }
  pTabList = p->pSrc;
  pEList = p->pEList;

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, p->pSrc);

  /* Look up every table named in the FROM clause of the select.  If
  ** an entry of the FROM clause is a subquery instead of a table or view,
  ** then create a transient table structure to describe the subquery.
  */
  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
    Table *pTab;
    if( pFrom->pTab!=0 ){
      /* This statement has already been prepared.  There is no need
      ** to go further. */
      assert( i==0 );
      return 0;
    }
    if( pFrom->zName==0 ){
#ifndef SQLITE_OMIT_SUBQUERY
      /* A sub-query in the FROM clause of a SELECT */
      assert( pFrom->pSelect!=0 );
      if( pFrom->zAlias==0 ){
        pFrom->zAlias =
          sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pFrom->pSelect);
      }
      assert( pFrom->pTab==0 );
      pFrom->pTab = pTab = 
        sqlite3ResultSetOfSelect(pParse, pFrom->zAlias, pFrom->pSelect);
      if( pTab==0 ){
        return 1;
      }
      /* The isEphem flag indicates that the Table structure has been
      ** dynamically allocated and may be freed at any time.  In other words,
      ** pTab is not pointing to a persistent table structure that defines
      ** part of the schema. */
      pTab->isEphem = 1;
#endif
    }else{
      /* An ordinary table or view name in the FROM clause */
      assert( pFrom->pTab==0 );
      pFrom->pTab = pTab = 
        sqlite3LocateTable(pParse,pFrom->zName,pFrom->zDatabase);
      if( pTab==0 ){
        return 1;
      }
      pTab->nRef++;
#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
      if( pTab->pSelect || IsVirtual(pTab) ){
        /* We reach here if the named table is a really a view */
        if( sqlite3ViewGetColumnNames(pParse, pTab) ){
          return 1;
        }
        /* If pFrom->pSelect!=0 it means we are dealing with a
        ** view within a view.  The SELECT structure has already been
        ** copied by the outer view so we can skip the copy step here
        ** in the inner view.
        */
        if( pFrom->pSelect==0 ){
          pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect);
        }
      }
#endif
    }
  }

  /* Process NATURAL keywords, and ON and USING clauses of joins.
  */
  if( sqliteProcessJoin(pParse, p) ) return 1;

  /* For every "*" that occurs in the column list, insert the names of
  ** all columns in all tables.  And for every TABLE.* insert the names
  ** of all columns in TABLE.  The parser inserted a special expression
  ** with the TK_ALL operator for each "*" that it found in the column list.
  ** The following code just has to locate the TK_ALL expressions and expand
  ** each one to the list of all columns in all tables.
  **
  ** The first loop just checks to see if there are any "*" operators
  ** that need expanding.
  */
  for(k=0; k<pEList->nExpr; k++){
    Expr *pE = pEList->a[k].pExpr;
    if( pE->op==TK_ALL ) break;
    if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
         && pE->pLeft && pE->pLeft->op==TK_ID ) break;
  }
  rc = 0;
  if( k<pEList->nExpr ){
    /*
    ** If we get here it means the result set contains one or more "*"
    ** operators that need to be expanded.  Loop through each expression
    ** in the result set and expand them one by one.
    */
    struct ExprList_item *a = pEList->a;
    ExprList *pNew = 0;
    int flags = pParse->db->flags;
    int longNames = (flags & SQLITE_FullColNames)!=0 &&
                      (flags & SQLITE_ShortColNames)==0;

    for(k=0; k<pEList->nExpr; k++){
      Expr *pE = a[k].pExpr;
      if( pE->op!=TK_ALL &&
           (pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
        /* This particular expression does not need to be expanded.
        */
        pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr, 0);
        if( pNew ){
          pNew->a[pNew->nExpr-1].zName = a[k].zName;
        }else{
          rc = 1;
        }
        a[k].pExpr = 0;
        a[k].zName = 0;
      }else{
        /* This expression is a "*" or a "TABLE.*" and needs to be
        ** expanded. */
        int tableSeen = 0;      /* Set to 1 when TABLE matches */
        char *zTName;            /* text of name of TABLE */
        if( pE->op==TK_DOT && pE->pLeft ){
          zTName = sqlite3NameFromToken(db, &pE->pLeft->token);
        }else{
          zTName = 0;
        }
        for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
          Table *pTab = pFrom->pTab;
          char *zTabName = pFrom->zAlias;
          if( zTabName==0 || zTabName[0]==0 ){ 
            zTabName = pTab->zName;
          }
          if( zTName && (zTabName==0 || zTabName[0]==0 || 
                 sqlite3StrICmp(zTName, zTabName)!=0) ){
            continue;
          }
          tableSeen = 1;
          for(j=0; j<pTab->nCol; j++){
            Expr *pExpr, *pRight;
            char *zName = pTab->aCol[j].zName;

            /* If a column is marked as 'hidden' (currently only possible
            ** for virtual tables), do not include it in the expanded
            ** result-set list.
            */
            if( IsHiddenColumn(&pTab->aCol[j]) ){
              assert(IsVirtual(pTab));
              continue;
            }

            if( i>0 ){
              struct SrcList_item *pLeft = &pTabList->a[i-1];
              if( (pLeft[1].jointype & JT_NATURAL)!=0 &&
                        columnIndex(pLeft->pTab, zName)>=0 ){
                /* In a NATURAL join, omit the join columns from the 
                ** table on the right */
                continue;
              }
              if( sqlite3IdListIndex(pLeft[1].pUsing, zName)>=0 ){
                /* In a join with a USING clause, omit columns in the
                ** using clause from the table on the right. */
                continue;
              }
            }
            pRight = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
            if( pRight==0 ) break;
            setQuotedToken(pParse, &pRight->token, zName);
            if( zTabName && (longNames || pTabList->nSrc>1) ){
              Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, 0);
              pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
              if( pExpr==0 ) break;
              setQuotedToken(pParse, &pLeft->token, zTabName);
              setToken(&pExpr->span, 
                  sqlite3MPrintf(db, "%s.%s", zTabName, zName));
              pExpr->span.dyn = 1;
              pExpr->token.z = 0;
              pExpr->token.n = 0;
              pExpr->token.dyn = 0;
            }else{
              pExpr = pRight;
              pExpr->span = pExpr->token;
              pExpr->span.dyn = 0;
            }
            if( longNames ){
              pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pExpr->span);
            }else{
              pNew = sqlite3ExprListAppend(pParse, pNew, pExpr, &pRight->token);
            }
          }
        }
        if( !tableSeen ){
          if( zTName ){
            sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
          }else{
            sqlite3ErrorMsg(pParse, "no tables specified");
          }
          rc = 1;
        }
        sqlite3_free(zTName);
      }
    }
    sqlite3ExprListDelete(pEList);
    p->pEList = pNew;
  }
  if( p->pEList && p->pEList->nExpr>SQLITE_MAX_COLUMN ){
    sqlite3ErrorMsg(pParse, "too many columns in result set");
    rc = SQLITE_ERROR;
  }
  if( db->mallocFailed ){
    rc = SQLITE_NOMEM;
  }
  return rc;
}

/*
** pE is a pointer to an expression which is a single term in
** ORDER BY or GROUP BY clause.
**
** If pE evaluates to an integer constant i, then return i.
** This is an indication to the caller that it should sort
** by the i-th column of the result set.
**
** If pE is a well-formed expression and the SELECT statement
** is not compound, then return 0.  This indicates to the
** caller that it should sort by the value of the ORDER BY
** expression.
**
** If the SELECT is compound, then 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.  If there is
** no match, return -1 and leave an error message in pParse.
*/
static int matchOrderByTermToExprList(
  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 idx,           /* When ORDER BY term is this */
  int isCompound,    /* True if this is a compound SELECT */
  u8 *pHasAgg        /* True if expression contains aggregate functions */
){
  int i;             /* Loop counter */
  ExprList *pEList;  /* The columns of the result set */
  NameContext nc;    /* Name context for resolving pE */


  /* If the term is an integer constant, return the value of that
  ** constant */
  pEList = pSelect->pEList;
  if( sqlite3ExprIsInteger(pE, &i) ){
    if( i<=0 ){
      /* If i is too small, make it too big.  That way the calling
      ** function still sees a value that is out of range, but does
      ** not confuse the column number with 0 or -1 result code.
      */
      i = pEList->nExpr+1;
    }
    return i;
  }

  /* If the term is a simple identifier that try to match that identifier
  ** against a column name in the result set.
  */
  if( pE->op==TK_ID || (pE->op==TK_STRING && pE->token.z[0]!='\'') ){
    sqlite3 *db = pParse->db;
    char *zCol = sqlite3NameFromToken(db, &pE->token);
    if( zCol==0 ){
      return -1;
    }
    for(i=0; i<pEList->nExpr; i++){
      char *zAs = pEList->a[i].zName;
      if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
        sqlite3_free(zCol);
        return i+1;
      }
    }
    sqlite3_free(zCol);
  }

  /* 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;
  if( sqlite3ExprResolveNames(&nc, pE) ){
    if( isCompound ){
      sqlite3ErrorClear(pParse);
      return 0;
    }else{
      return -1;
    }
  }
  if( nc.hasAgg && pHasAgg ){
    *pHasAgg = 1;
  }

  /* For a compound SELECT, we need to try to match the ORDER BY
  ** expression against an expression in the result set
  */
  if( isCompound ){
    for(i=0; i<pEList->nExpr; i++){
      if( sqlite3ExprCompare(pEList->a[i].pExpr, pE) ){
        return i+1;
      }
    }
  }
  return 0;
}


/*
** Analyze and ORDER BY or GROUP BY clause in a simple SELECT statement.
** Return the number of errors seen.
**
** Every term of the ORDER BY or GROUP BY clause needs to be an
** expression.  If any expression is an integer constant, then
** that expression is replaced by the corresponding 
** expression from the result set.
*/
static int processOrderGroupBy(
  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 */
  int isOrder,          /* 1 for ORDER BY.  0 for GROUP BY */
  u8 *pHasAgg           /* Set to TRUE if any term contains an aggregate */
){
  int i;
  sqlite3 *db = pParse->db;
  ExprList *pEList;

  if( pOrderBy==0 ) return 0;
  if( pOrderBy->nExpr>SQLITE_MAX_COLUMN ){
    const char *zType = isOrder ? "ORDER" : "GROUP";
    sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
    return 1;
  }
  pEList = pSelect->pEList;
  if( pEList==0 ){
    return 0;
  }
  for(i=0; i<pOrderBy->nExpr; i++){
    int iCol;
    Expr *pE = pOrderBy->a[i].pExpr;
    iCol = matchOrderByTermToExprList(pParse, pSelect, pE, i+1, 0, pHasAgg);
    if( iCol<0 ){
      return 1;
    }
    if( iCol>pEList->nExpr ){
      const char *zType = isOrder ? "ORDER" : "GROUP";
      sqlite3ErrorMsg(pParse, 
         "%r %s BY term out of range - should be "
         "between 1 and %d", i+1, zType, pEList->nExpr);
      return 1;
    }
    if( iCol>0 ){
      CollSeq *pColl = pE->pColl;
      int flags = pE->flags & EP_ExpCollate;
      sqlite3ExprDelete(pE);
      pE = sqlite3ExprDup(db, pEList->a[iCol-1].pExpr);
      pOrderBy->a[i].pExpr = pE;
      if( pColl && flags ){
        pE->pColl = pColl;
        pE->flags |= flags;
      }
    }
  }
  return 0;
}

/*
** Analyze and ORDER BY or GROUP BY clause in a SELECT statement.  Return
** the number of errors seen.
**
** The processing depends on whether the SELECT is simple or compound.
** For a simple SELECT statement, evry term of the ORDER BY or GROUP BY
** clause needs to be an expression.  If any expression is an integer
** constant, then that expression is replaced by the corresponding 
** expression from the result set.
**
** For compound SELECT statements, every expression needs to be of
** type TK_COLUMN with a iTable value as given in the 4th parameter.
** If any expression is an integer, that becomes the column number.
** Otherwise, match the expression against result set columns from
** the left-most SELECT.
*/
static int processCompoundOrderBy(
  Parse *pParse,        /* Parsing context.  Leave error messages here */
  Select *pSelect,      /* The SELECT statement containing the ORDER BY */
  int iTable            /* Output table for compound SELECT statements */
){
  int i;
  ExprList *pOrderBy;
  ExprList *pEList;