}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:
**

  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);

  /* Translate the schema name in zDb into a pointer to the corresponding
  ** schema.  If not found, pSchema will remain NULL and nothing will match
  ** resulting in an appropriate error message toward the end of this routine
  */
  if( zDb ){
    for(i=0; i<db->nDb; i++){
      assert( db->aDb[i].zName );
      if( sqlite3StrICmp(db->aDb[i].zName,zDb)==0 ){
        pSchema = db->aDb[i].pSchema;
        break;
      }
    }
  }

  /* 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;

        Column *pCol;
  
        pTab = pItem->pTab;
        assert( pTab!=0 && pTab->zName!=0 );

        assert( pTab->nCol>0 );
        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;
              hit = 1;
            }
          }
          if( hit || zTab==0 ) continue;

        }
        if( zDb && pTab->pSchema!=pSchema ){

          continue;
        }
        if( zTab ){
          const char *zTabName = pItem->zAlias ? pItem->zAlias : pTab->zName;
          assert( zTabName!=0 );
          if( sqlite3StrICmp(zTabName, zTab)!=0 ){
            continue;
          }
        }

        if( 0==(cntTab++) ){



          pMatch = pItem;
        }
        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
            /* If there has been exactly one prior match and this match
            ** is for the right-hand table of a NATURAL JOIN or is in a 
            ** USING clause, then skip this match.
            */
            if( cnt==1 ){
              if( pItem->jointype & JT_NATURAL ) continue;
              if( nameInUsingClause(pItem->pUsing, zCol) ) continue;
            }
            cnt++;


            pMatch = pItem;

            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
            pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
            break;
          }
        }
      }
      if( pMatch ){
        pExpr->iTable = pMatch->iCursor;
        pExpr->pTab = pMatch->pTab;
        pSchema = pExpr->pTab->pSchema;
      }
    } /* if( pSrcList ) */

#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;

  *pnCol = nCol;
  *paCol = aCol;

  for(i=0, pCol=aCol; i<nCol; i++, pCol++){
    /* Get an appropriate name for the column
    */
    p = sqlite3ExprSkipCollate(pEList->a[i].pExpr);


    if( (zName = pEList->a[i].zName)!=0 ){
      /* If the column contains an "AS <name>" phrase, use <name> as the name */
      zName = sqlite3DbStrDup(db, zName);
    }else{
      Expr *pColExpr = p;  /* The expression that is the result column name */
      Table *pTab;         /* Table associated with this expression */
      while( pColExpr->op==TK_DOT ){

    /* Make sure the column name is unique.  If the name is not unique,
    ** append a integer to the name so that it becomes unique.
    */
    nName = sqlite3Strlen30(zName);
    for(j=cnt=0; j<i; j++){
      if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
        char *zNewName;
        int k;
        for(k=nName-1; k>1 && sqlite3Isdigit(zName[k]); k--){}
        if( zName[k]==':' ) nName = k;
        zName[nName] = 0;
        zNewName = sqlite3MPrintf(db, "%s:%d", zName, ++cnt);
        sqlite3DbFree(db, zName);
        zName = zNewName;
        j = -1;
        if( zName==0 ) break;
      }

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;

    /* When processing FROM-clause subqueries, it is always the case
    ** that full_column_names=OFF and short_column_names=ON.  The
    ** sqlite3ResultSetOfSelect() routine makes it so. */
    assert( (p->selFlags & SF_NestedFrom)==0
          || ((flags & SQLITE_FullColNames)==0 &&
              (flags & SQLITE_ShortColNames)!=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;
          int iDb;
          if( zTabName==0 ){
            zTabName = pTab->zName;
          }
          if( db->mallocFailed ) break;
          if( pSub==0 || (pSub->selFlags & SF_NestedFrom)==0 ){
            pSub = 0;
            if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
              continue;
            }
            iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
            zSchemaName = iDb>=0 ? db->aDb[iDb].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 */

            assert( zName );
            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 */

            pRight = sqlite3Expr(db, TK_ID, zName);
            zColname = zName;
            zToFree = 0;
            if( longNames || pTabList->nSrc>1 ){
              Expr *pLeft;
              pLeft = sqlite3Expr(db, TK_ID, zTabName);
              pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
              if( zSchemaName ){
                pLeft = sqlite3Expr(db, TK_ID, zSchemaName);
                pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pExpr, 0);
              }
              if( longNames ){
                zColname = sqlite3MPrintf(db, "%s.%s", zTabName, zName);
                zToFree = zColname;
              }
            }else{
              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);
                testcase( pX->zSpan==0 );
              }else{
                pX->zSpan = sqlite3MPrintf(db, "%s.%s.%s",
                                           zSchemaName, zTabName, zColname);
                testcase( pX->zSpan==0 );
              }
              pX->bSpanIsTab = 1;
            }
            sqlite3DbFree(db, zToFree);
          }
        }
        if( !tableSeen ){
          if( zTName ){
            sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
          }else{

/*
** A list of expressions.  Each expression may optionally have a
** name.  An expr/name combination can be used in several ways, such
** as the list of "expr AS ID" fields following a "SELECT" or in the
** list of "ID = expr" items in an UPDATE.  A list of expressions can
** also be used as the argument to a function, in which case the a.zName
** 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
** the parse tree for an expression and the span of input text for an
** expression.

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*);

# 2012 December 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 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-$i.0 {
    db eval {
      ATTACH ':memory:' AS aux1;
      CREATE TABLE t1(a,b); INSERT INTO t1 VALUES(111,'x1');
      CREATE TABLE t2(a,b); INSERT INTO t2 VALUES(222,'x2');
      CREATE TEMP TABLE t3(a,b); INSERT INTO t3 VALUES(333,'x3');
      CREATE TABLE main.t4(a,b); INSERT INTO main.t4 VALUES(444,'x4');
      CREATE TABLE aux1.t4(a,b); INSERT INTO aux1.t4 VALUES(555,'x5');
    }
  } {}
  do_test selectD-$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-$i.2.4 {
    db eval {
      SELECT *
        FROM t1 JOIN (t2 JOIN (main.t4 JOIN aux1.t4 ON aux1.t4.a=main.t4.a+111)
                              ON main.t4.a=t2.a+222)
                     ON t2.a=t1.a+111;
    }
  } {111 x1 222 x2 444 x4 555 x5}
  do_test selectD-$i.2.5 {
    db eval {
      SELECT *
        FROM t1 JOIN (t2 JOIN (main.t4 AS x JOIN aux1.t4 ON aux1.t4.a=x.a+111)
                              ON x.a=t2.a+222)
                     ON t2.a=t1.a+111;
    }
  } {111 x1 222 x2 444 x4 555 x5}
  do_test selectD-$i.2.6 {
    catchsql {
      SELECT *
        FROM t1 JOIN (t2 JOIN (main.t4 JOIN aux.t4 ON aux.t4.a=main.t4.a+111)
                              ON main.t4.a=t2.a+222)
                     ON t2.a=t1.a+111;
    }
  } {1 {no such table: aux.t4}}
  do_test selectD-$i.2.7 {
    db eval {
      SELECT x.a, y.b
        FROM t1 JOIN (t2 JOIN (main.t4 x JOIN aux1.t4 y ON y.a=x.a+111)
                              ON x.a=t2.a+222)
                     ON t2.a=t1.a+111;
    }
  } {444 x5}
  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