return 0;
  }
  /* The sqlite3ResultSetOfSelect() is only used n contexts where lookaside
  ** is disabled */
  assert( db->lookaside.bEnabled==0 );
  pTab->nRef = 1;
  pTab->zName = 0;

  selectColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
  selectAddColumnTypeAndCollation(pParse, pTab->nCol, pTab->aCol, pSelect);
  pTab->iPKey = -1;
  if( db->mallocFailed ){
    sqlite3DeleteTable(db, pTab);
    return 0;
  }
................................................................................
      pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
      if( pTab==0 ) return WRC_Abort;
      pTab->nRef = 1;
      pTab->zName = sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pTab);
      while( pSel->pPrior ){ pSel = pSel->pPrior; }
      selectColumnsFromExprList(pParse, pSel->pEList, &pTab->nCol, &pTab->aCol);
      pTab->iPKey = -1;

      pTab->tabFlags |= TF_Ephemeral;
#endif
    }else{
      /* An ordinary table or view name in the FROM clause */
      assert( pFrom->pTab==0 );
      pFrom->pTab = pTab = 
        sqlite3LocateTable(pParse,0,pFrom->zName,pFrom->zDatabase);

    return 0;
  }
  /* The sqlite3ResultSetOfSelect() is only used n contexts where lookaside
  ** is disabled */
  assert( db->lookaside.bEnabled==0 );
  pTab->nRef = 1;
  pTab->zName = 0;
  pTab->nRowEst = 1000000;
  selectColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
  selectAddColumnTypeAndCollation(pParse, pTab->nCol, pTab->aCol, pSelect);
  pTab->iPKey = -1;
  if( db->mallocFailed ){
    sqlite3DeleteTable(db, pTab);
    return 0;
  }
................................................................................
      pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
      if( pTab==0 ) return WRC_Abort;
      pTab->nRef = 1;
      pTab->zName = sqlite3MPrintf(db, "sqlite_subquery_%p_", (void*)pTab);
      while( pSel->pPrior ){ pSel = pSel->pPrior; }
      selectColumnsFromExprList(pParse, pSel->pEList, &pTab->nCol, &pTab->aCol);
      pTab->iPKey = -1;
      pTab->nRowEst = 1000000;
      pTab->tabFlags |= TF_Ephemeral;
#endif
    }else{
      /* An ordinary table or view name in the FROM clause */
      assert( pFrom->pTab==0 );
      pFrom->pTab = pTab = 
        sqlite3LocateTable(pParse,0,pFrom->zName,pFrom->zDatabase);

  db eval {
    EXPLAIN QUERY PLAN
    SELECT b FROM t501
     WHERE t501.a=123
       AND t501.a IN (SELECT x FROM t502 WHERE y=t501.b);
  }
} {0 0 {TABLE t501 USING PRIMARY KEY} 0 0 {TABLE t502}}
    








































































finish_test

  db eval {
    EXPLAIN QUERY PLAN
    SELECT b FROM t501
     WHERE t501.a=123
       AND t501.a IN (SELECT x FROM t502 WHERE y=t501.b);
  }
} {0 0 {TABLE t501 USING PRIMARY KEY} 0 0 {TABLE t502}}


# The following code checks a performance regression reported on the
# mailing list on 2010-10-19.  The problem is that the nRowEst field
# of ephermeral tables was not being initialized correctly and so no
# automatic index was being created for the emphemeral table when it was
# used as part of a join.
#
do_test autoindex1-600 {
  db eval {
    CREATE TABLE flock_owner(
      owner_rec_id INTEGER CONSTRAINT flock_owner_key PRIMARY KEY,
      flock_no VARCHAR(6) NOT NULL REFERENCES flock (flock_no),
      owner_person_id INTEGER NOT NULL REFERENCES person (person_id),
      owner_change_date TEXT, last_changed TEXT NOT NULL,
      CONSTRAINT fo_owner_date UNIQUE (flock_no, owner_change_date)
    );
    CREATE TABLE sheep (
      Sheep_No char(7) NOT NULL,
      Date_of_Birth char(8),
      Sort_DoB text,
      Flock_Book_Vol char(2),
      Breeder_No char(6),
      Breeder_Person integer,
      Originating_Flock char(6),
      Registering_Flock char(6),
      Tag_Prefix char(9),
      Tag_No char(15),
      Sort_Tag_No integer,
      Breeders_Temp_Tag char(15),
      Sex char(1),
      Sheep_Name char(32),
      Sire_No char(7),
      Dam_No char(7),
      Register_Code char(1),
      Colour char(48),
      Colour_Code char(2),
      Pattern_Code char(8),
      Horns char(1),
      Litter_Size char(1),
      Coeff_of_Inbreeding real,
      Date_of_Registration text,
      Date_Last_Changed text,
      UNIQUE(Sheep_No));
    CREATE INDEX fo_flock_no_index  
                ON flock_owner (flock_no);
    CREATE INDEX fo_owner_change_date_index  
                ON flock_owner (owner_change_date);
    CREATE INDEX fo_owner_person_id_index  
                ON flock_owner (owner_person_id);
    CREATE INDEX sheep_org_flock_index  
             ON sheep (originating_flock);
    CREATE INDEX sheep_reg_flock_index  
             ON sheep (registering_flock);
    EXPLAIN QUERY PLAN
    SELECT x.sheep_no, x.registering_flock, x.date_of_registration
     FROM sheep x LEFT JOIN
         (SELECT s.sheep_no, prev.flock_no, prev.owner_person_id,
         s.date_of_registration, prev.owner_change_date
         FROM sheep s JOIN flock_owner prev ON s.registering_flock =
     prev.flock_no
         AND (prev.owner_change_date <= s.date_of_registration || ' 00:00:00')
         WHERE NOT EXISTS
             (SELECT 'x' FROM flock_owner later
             WHERE prev.flock_no = later.flock_no
             AND later.owner_change_date > prev.owner_change_date
             AND later.owner_change_date <= s.date_of_registration||' 00:00:00')
         ) y ON x.sheep_no = y.sheep_no
     WHERE y.sheep_no IS NULL
     ORDER BY x.registering_flock;
  }
} {0 0 {TABLE sheep AS s} 1 1 {TABLE flock_owner AS prev WITH INDEX sqlite_autoindex_flock_owner_1} 0 0 {TABLE flock_owner AS later WITH INDEX sqlite_autoindex_flock_owner_1} 0 0 {TABLE sheep AS x WITH INDEX sheep_reg_flock_index ORDER BY} 1 1 {TABLE  AS y WITH AUTOMATIC INDEX}}

finish_test