pLimit = p->pLimit;
        p->pLimit = 0;
        uniondest.eDest = op;
        ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE",
                          selectOpName(p->op)));
        rc = sqlite3Select(pParse, p, &uniondest);
        testcase( rc!=SQLITE_OK );
        /* Query flattening in sqlite3Select() might refill p->pOrderBy.
        ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
        sqlite3ExprListDelete(db, p->pOrderBy);
        pDelete = p->pPrior;
        p->pPrior = pPrior;
        p->pOrderBy = 0;
        if( p->op==TK_UNION ){
          p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
        }
        sqlite3ExprDelete(db, p->pLimit);
................................................................................
    **   SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
    **   \                     \_____________ subquery __________/          /
    **    \_____________________ outer query ______________________________/
    **
    ** We look at every expression in the outer query and every place we see
    ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
    */
    if( pSub->pOrderBy ){
      /* At this point, any non-zero iOrderByCol values indicate that the
      ** ORDER BY column expression is identical to the iOrderByCol'th
      ** expression returned by SELECT statement pSub. Since these values
      ** do not necessarily correspond to columns in SELECT statement pParent,
      ** zero them before transfering the ORDER BY clause.
      **
      ** Not doing this may cause an error if a subsequent call to this
................................................................................
           pDest->eDest==SRT_Queue  || pDest->eDest==SRT_DistFifo ||
           pDest->eDest==SRT_DistQueue || pDest->eDest==SRT_Fifo);
    /* If ORDER BY makes no difference in the output then neither does
    ** DISTINCT so it can be removed too. */
    sqlite3ExprListDelete(db, p->pOrderBy);
    p->pOrderBy = 0;
    p->selFlags &= ~SF_Distinct;

  }
  sqlite3SelectPrep(pParse, p, 0);
  if( pParse->nErr || db->mallocFailed ){
    goto select_end;
  }
  assert( p->pEList!=0 );
#if SELECTTRACE_ENABLED

        pLimit = p->pLimit;
        p->pLimit = 0;
        uniondest.eDest = op;
        ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE",
                          selectOpName(p->op)));
        rc = sqlite3Select(pParse, p, &uniondest);
        testcase( rc!=SQLITE_OK );


        assert( p->pOrderBy==0 );
        pDelete = p->pPrior;
        p->pPrior = pPrior;
        p->pOrderBy = 0;
        if( p->op==TK_UNION ){
          p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
        }
        sqlite3ExprDelete(db, p->pLimit);
................................................................................
    **   SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
    **   \                     \_____________ subquery __________/          /
    **    \_____________________ outer query ______________________________/
    **
    ** We look at every expression in the outer query and every place we see
    ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
    */
    if( pSub->pOrderBy && (pParent->selFlags & SF_NoopOrderBy)==0 ){
      /* At this point, any non-zero iOrderByCol values indicate that the
      ** ORDER BY column expression is identical to the iOrderByCol'th
      ** expression returned by SELECT statement pSub. Since these values
      ** do not necessarily correspond to columns in SELECT statement pParent,
      ** zero them before transfering the ORDER BY clause.
      **
      ** Not doing this may cause an error if a subsequent call to this
................................................................................
           pDest->eDest==SRT_Queue  || pDest->eDest==SRT_DistFifo ||
           pDest->eDest==SRT_DistQueue || pDest->eDest==SRT_Fifo);
    /* If ORDER BY makes no difference in the output then neither does
    ** DISTINCT so it can be removed too. */
    sqlite3ExprListDelete(db, p->pOrderBy);
    p->pOrderBy = 0;
    p->selFlags &= ~SF_Distinct;
    p->selFlags |= SF_NoopOrderBy;
  }
  sqlite3SelectPrep(pParse, p, 0);
  if( pParse->nErr || db->mallocFailed ){
    goto select_end;
  }
  assert( p->pEList!=0 );
#if SELECTTRACE_ENABLED

#define SF_MaybeConvert  0x0008000 /* Need convertCompoundSelectToSubquery() */
#define SF_Converted     0x0010000 /* By convertCompoundSelectToSubquery() */
#define SF_IncludeHidden 0x0020000 /* Include hidden columns in output */
#define SF_ComplexResult 0x0040000 /* Result contains subquery or function */
#define SF_WhereBegin    0x0080000 /* Really a WhereBegin() call.  Debug Only */
#define SF_WinRewrite    0x0100000 /* Window function rewrite accomplished */
#define SF_View          0x0200000 /* SELECT statement is a view */


/*
** The results of a SELECT can be distributed in several ways, as defined
** by one of the following macros.  The "SRT" prefix means "SELECT Result
** Type".
**
**     SRT_Union       Store results as a key in a temporary index

#define SF_MaybeConvert  0x0008000 /* Need convertCompoundSelectToSubquery() */
#define SF_Converted     0x0010000 /* By convertCompoundSelectToSubquery() */
#define SF_IncludeHidden 0x0020000 /* Include hidden columns in output */
#define SF_ComplexResult 0x0040000 /* Result contains subquery or function */
#define SF_WhereBegin    0x0080000 /* Really a WhereBegin() call.  Debug Only */
#define SF_WinRewrite    0x0100000 /* Window function rewrite accomplished */
#define SF_View          0x0200000 /* SELECT statement is a view */
#define SF_NoopOrderBy   0x0400000 /* ORDER BY is ignored for this query */

/*
** The results of a SELECT can be distributed in several ways, as defined
** by one of the following macros.  The "SRT" prefix means "SELECT Result
** Type".
**
**     SRT_Union       Store results as a key in a temporary index

  DROP TABLE IF EXISTS t2;
  CREATE TABLE t1(a INTEGER);
  CREATE TABLE t2(b TEXT);
  INSERT INTO t2(b) VALUES('12345');
  SELECT * FROM (SELECT a FROM t1 UNION SELECT b FROM t2) WHERE a=a;
} {12345}























finish_test

  DROP TABLE IF EXISTS t2;
  CREATE TABLE t1(a INTEGER);
  CREATE TABLE t2(b TEXT);
  INSERT INTO t2(b) VALUES('12345');
  SELECT * FROM (SELECT a FROM t1 UNION SELECT b FROM t2) WHERE a=a;
} {12345}

# 2020-06-15 ticket 8f157e8010b22af0
#
reset_db
do_execsql_test 7.1 {
  CREATE TABLE t1(c1);     INSERT INTO t1 VALUES(12),(123),(1234),(NULL),('abc');
  CREATE TABLE t2(c2);     INSERT INTO t2 VALUES(44),(55),(123);
  CREATE TABLE t3(c3,c4);  INSERT INTO t3 VALUES(66,1),(123,2),(77,3);
  CREATE VIEW t4 AS SELECT c3 FROM t3;
  CREATE VIEW t5 AS SELECT c3 FROM t3 ORDER BY c4;
}
do_execsql_test 7.2 {
  SELECT * FROM t1, t2 WHERE c1=(SELECT 123 INTERSECT SELECT c2 FROM t4) AND c1=123;
} {123 123}
do_execsql_test 7.3 {
  SELECT * FROM t1, t2 WHERE c1=(SELECT 123 INTERSECT SELECT c2 FROM t5) AND c1=123;
} {123 123}
do_execsql_test 7.4 {
  CREATE TABLE a(b);
  CREATE VIEW c(d) AS SELECT b FROM a ORDER BY b;
  SELECT sum(d) OVER( PARTITION BY(SELECT 0 FROM c JOIN a WHERE b =(SELECT b INTERSECT SELECT d FROM c) AND b = 123)) FROM c;
} {}

finish_test