SQLite

  }else{
    sqlite3ExplainPush(pOut);
    for(i=0; i<pList->nExpr; i++){
      sqlite3ExplainPrintf(pOut, "item[%d] = ", i);
      sqlite3ExplainPush(pOut);
      sqlite3ExplainExpr(pOut, pList->a[i].pExpr);
      sqlite3ExplainPop(pOut);
      if( pList->a[i].zName ){
        sqlite3ExplainPrintf(pOut, " AS %s", pList->a[i].zName);
      }
      if( pList->a[i].bSpanIsTab ){
        sqlite3ExplainPrintf(pOut, " (%s)", pList->a[i].zSpan);
      }
      if( i<pList->nExpr-1 ){
        sqlite3ExplainNL(pOut);
      }
    }
    sqlite3ExplainPop(pOut);
  }
}

    for(k=0; k<pUsing->nId; k++){
      if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ) return 1;
    }
  }
  return 0;
}

/*
** Subqueries stores the original database, table and column names for their
** result sets in ExprList.a[].zSpan, in the form "DATABASE.TABLE.COLUMN".
** Check to see if the zSpan given to this routine matches the zDb, zTab,
** and zCol.  If any of zDb, zTab, and zCol are NULL then those fields will
** match anything.
*/
int sqlite3MatchSpanName(
  const char *zSpan,
  const char *zCol,
  const char *zTab,
  const char *zDb
){
  int n;
  for(n=0; ALWAYS(zSpan[n]) && zSpan[n]!='.'; n++){}
  if( zDb && sqlite3StrNICmp(zSpan, zDb, n)!=0 ){
    return 0;
  }
  zSpan += n+1;
  for(n=0; ALWAYS(zSpan[n]) && zSpan[n]!='.'; n++){}
  if( zTab && sqlite3StrNICmp(zSpan, zTab, n)!=0 ){
    return 0;
  }
  zSpan += n+1;
  if( zCol && sqlite3StrICmp(zSpan, zCol)!=0 ){
    return 0;
  }
  return 1;
}

/*
** 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:
**

        if( zDb && pTab->pSchema!=pSchema ){
          continue;
        }
        if( pItem->pSelect && (pItem->pSelect->selFlags & SF_NestedFrom)!=0 ){
          ExprList *pEList = pItem->pSelect->pEList;
          int hit = 0;
          for(j=0; j<pEList->nExpr; j++){
            if( sqlite3MatchSpanName(pEList->a[j].zSpan, zCol, zTab, zDb) ){

              cnt++;
              cntTab = 2;
              pMatch = pItem;
              pExpr->iColumn = j;
            }
          }
          if( hit || zTab==0 ) continue;

static int selectExpander(Walker *pWalker, Select *p){
  Parse *pParse = pWalker->pParse;
  int i, j, k;
  SrcList *pTabList;
  ExprList *pEList;
  struct SrcList_item *pFrom;
  sqlite3 *db = pParse->db;
  Expr *pE, *pRight, *pExpr;

  if( db->mallocFailed  ){
    return WRC_Abort;
  }
  if( NEVER(p->pSrc==0) || (p->selFlags & SF_Expanded)!=0 ){
    return WRC_Prune;
  }

  ** 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++){
    pE = pEList->a[k].pExpr;
    if( pE->op==TK_ALL ) break;
    assert( pE->op!=TK_DOT || pE->pRight!=0 );
    assert( pE->op!=TK_DOT || (pE->pLeft!=0 && pE->pLeft->op==TK_ID) );
    if( pE->op==TK_DOT && pE->pRight->op==TK_ALL ) break;
  }
  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
                      && (p->selFlags & SF_NestedFrom)==0;

    for(k=0; k<pEList->nExpr; k++){
      pE = a[k].pExpr;
      pRight = pE->pRight;
      assert( pE->op!=TK_DOT || pRight!=0 );
      if( pE->op!=TK_ALL && (pE->op!=TK_DOT || pRight->op!=TK_ALL) ){
        /* This particular expression does not need to be expanded.
        */
        pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr);
        if( pNew ){
          pNew->a[pNew->nExpr-1].zName = a[k].zName;
          pNew->a[pNew->nExpr-1].zSpan = a[k].zSpan;
          a[k].zName = 0;
          a[k].zSpan = 0;
        }
        a[k].pExpr = 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 = 0;       /* text of name of TABLE */
        if( pE->op==TK_DOT ){
          assert( pE->pLeft!=0 );
          assert( !ExprHasProperty(pE->pLeft, EP_IntValue) );
          zTName = pE->pLeft->u.zToken;


        }
        for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
          Table *pTab = pFrom->pTab;
          Select *pSub = pFrom->pSelect;
          char *zTabName = pFrom->zAlias;
          const char *zSchemaName = 0;
          if( zTabName==0 ){
            zTabName = pTab->zName;
          }
          if( db->mallocFailed ) break;
          if( pSub==0 || (pSub->selFlags & SF_NestedFrom)==0 ){
            int iDb;
            pSub = 0;
            if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
              continue;
            }
            iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
            zSchemaName = iDb>=0 ? db->aDb[i].zName : "*";
          }
          for(j=0; j<pTab->nCol; j++){

            char *zName = pTab->aCol[j].zName;
            char *zColname;  /* The computed column name */
            char *zToFree;   /* Malloced string that needs to be freed */
            Token sColname;  /* Computed column name as a token */

            if( zTName && pSub
             && sqlite3MatchSpanName(pSub->pEList->a[j].zSpan, 0, zTName, 0)==0
            ){
              continue;
            }

            /* 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;
            }
            tableSeen = 1;

            if( i>0 && zTName==0 ){
              if( (pFrom->jointype & JT_NATURAL)!=0
                && tableAndColumnIndex(pTabList, i, zName, 0, 0)
              ){
                /* In a NATURAL join, omit the join columns from the 
                ** table to the right of the join */

              pExpr = pRight;
            }
            pNew = sqlite3ExprListAppend(pParse, pNew, pExpr);
            sColname.z = zColname;
            sColname.n = sqlite3Strlen30(zColname);
            sqlite3ExprListSetName(pParse, pNew, &sColname, 0);
            if( pNew && (p->selFlags & SF_NestedFrom)!=0 ){
              struct ExprList_item *pX = &pNew->a[pNew->nExpr-1];
              if( pSub ){
                pX->zSpan = sqlite3DbStrDup(db, pSub->pEList->a[j].zSpan);
              }else{
                pX->zSpan = sqlite3MPrintf(db, "%s.%s.%s",
                                           zSchemaName, zTabName, zColname);
              }
              pX->bSpanIsTab = 1;
            }
            sqlite3DbFree(db, zToFree);
          }
        }
        if( !tableSeen ){
          if( zTName ){
            sqlite3ErrorMsg(pParse, "no such table: %s", zTName);

** field is not used.
**
** By default the Expr.zSpan field holds a human-readable description of
** the expression that is used in the generation of error messages and
** column labels.  In this case, Expr.zSpan is typically the text of a
** column expression as it exists in a SELECT statement.  However, if
** the bSpanIsTab flag is set, then zSpan is overloaded to mean the name
** of the result column in the form: DATABASE.TABLE.COLUMN.  This later
** form is used for name resolution with nested FROM clauses.
*/
struct ExprList {
  int nExpr;             /* Number of expressions on the list */
  int iECursor;          /* VDBE Cursor associated with this ExprList */
  struct ExprList_item { /* For each expression in the list */
    Expr *pExpr;            /* The list of expressions */
    char *zName;            /* Token associated with this expression */
    char *zSpan;            /* Original text of the expression */
    u8 sortOrder;           /* 1 for DESC or 0 for ASC */
    unsigned done :1;       /* A flag to indicate when processing is finished */
    unsigned bSpanIsTab :1; /* zSpan holds DB.TABLE.COLUMN */
    u16 iOrderByCol;        /* For ORDER BY, column number in result set */
    u16 iAlias;             /* Index into Parse.aAlias[] for zName */
  } *a;                  /* Alloc a power of two greater or equal to nExpr */
};

/*
** An instance of this structure is used by the parser to record both

void sqlite3AlterFunctions(void);
void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
int sqlite3GetToken(const unsigned char *, int *);
void sqlite3NestedParse(Parse*, const char*, ...);
void sqlite3ExpirePreparedStatements(sqlite3*);
int sqlite3CodeSubselect(Parse *, Expr *, int, int);
void sqlite3SelectPrep(Parse*, Select*, NameContext*);
int sqlite3MatchSpanName(const char*, const char*, const char*, const char*);
int sqlite3ResolveExprNames(NameContext*, Expr*);
void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);
int sqlite3ResolveOrderGroupBy(Parse*, Select*, ExprList*, const char*);
void sqlite3ColumnDefault(Vdbe *, Table *, int, int);
void sqlite3AlterFinishAddColumn(Parse *, Token *);
void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
CollSeq *sqlite3GetCollSeq(Parse*, u8, CollSeq *, const char*);

# This file implements regression tests for name resolution in SELECT
# statements that have parenthesized FROM clauses.
#

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


for {set i 1} {$i<=2} {incr i} {
  db close
  forcedelete test$i.db
  sqlite3 db test$i.db
  if {$i==2} {
    optimization_control db query-flattener off
  }
  do_test selectD-$i.0 {
    db eval {
      CREATE TABLE t1(a,b); INSERT INTO t1 VALUES(111,'x1');
      CREATE TABLE t2(a,b); INSERT INTO t2 VALUES(222,'x2');
      CREATE TEMP TABLE t3(a,b); INSERT INTO t3 VALUES(333,'x3');
      CREATE TABLE t4(a,b); INSERT INTO t4 VALUES(444,'x4');
    }
  } {}
  do_test selectD-$i.1 {
    db eval {
      SELECT *
        FROM (t1), (t2), (t3), (t4)
       WHERE t4.a=t3.a+111 
         AND t3.a=t2.a+111
         AND t2.a=t1.a+111;
    }
  } {111 x1 222 x2 333 x3 444 x4}
  do_test selectD-$i.2.1 {
    db eval {
      SELECT *
        FROM t1 JOIN (t2 JOIN (t3 JOIN t4 ON t4.a=t3.a+111)
                              ON t3.a=t2.a+111)
                     ON t2.a=t1.a+111;
    }
  } {111 x1 222 x2 333 x3 444 x4}
  do_test selectD-$i.2.2 {
    db eval {
      SELECT t3.a
        FROM t1 JOIN (t2 JOIN (t3 JOIN t4 ON t4.a=t3.a+111)
                              ON t3.a=t2.a+111)
                     ON t2.a=t1.a+111;
    }
  } {333}
  do_test selectD-$i.2.3 {
    db eval {
      SELECT t3.*
        FROM t1 JOIN (t2 JOIN (t3 JOIN t4 ON t4.a=t3.a+111)
                              ON t3.a=t2.a+111)
                     ON t2.a=t1.a+111;
    }
  } {333 x3}
  do_test selectD-$i.2.3 {
    db eval {
      SELECT t3.*, t2.*
        FROM t1 JOIN (t2 JOIN (t3 JOIN t4 ON t4.a=t3.a+111)
                              ON t3.a=t2.a+111)
                     ON t2.a=t1.a+111;
    }
  } {333 x3 222 x2}
  do_test selectD-$i.3 {
    db eval {
      UPDATE t2 SET a=111;
      UPDATE t3 SET a=111;
      UPDATE t4 SET a=111;
      SELECT *
        FROM t1 JOIN (t2 JOIN (t3 JOIN t4 USING(a)) USING (a)) USING (a);
    }
  } {111 x1 x2 x3 x4}
  do_test selectD-$i.4 {
    db eval {
      UPDATE t2 SET a=111;
      UPDATE t3 SET a=111;
      UPDATE t4 SET a=111;
      SELECT *
        FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 USING(a))
                                        USING (a))
                           USING (a);
    }
  } {111 x1 x2 x3 x4}
  do_test selectD-$i.5 {
    db eval {
      UPDATE t3 SET a=222;
      UPDATE t4 SET a=222;
      SELECT *
        FROM (t1 LEFT JOIN t2 USING(a)) JOIN (t3 LEFT JOIN t4 USING(a))
             ON t1.a=t3.a-111;
    }
  } {111 x1 x2 222 x3 x4}
  do_test selectD-$i.6 {
    db eval {
      UPDATE t4 SET a=333;
      SELECT *
        FROM (t1 LEFT JOIN t2 USING(a)) JOIN (t3 LEFT JOIN t4 USING(a))
             ON t1.a=t3.a-111;
    }
  } {111 x1 x2 222 x3 {}}
  do_test selectD-$i.7 {
    db eval {
      SELECT t1.*, t2.*, t3.*, t4.b
        FROM (t1 LEFT JOIN t2 USING(a)) JOIN (t3 LEFT JOIN t4 USING(a))
             ON t1.a=t3.a-111;
    }
  } {111 x1 111 x2 222 x3 {}}
}

finish_test