**
**   (2)  The subquery is not an aggregate or (2a) the outer query is not a join
**        and (2b) the outer query does not use subqueries other than the one
**        FROM-clause subquery that is a candidate for flattening.  (2b is
**        due to ticket [2f7170d73bf9abf80] from 2015-02-09.)
**
**   (3)  The subquery is not the right operand of a LEFT JOIN
**        or the subquery is not itself a join and the outer query is not

**        an aggregate.
**
**   (4)  The subquery is not DISTINCT.
**
**  (**)  At one point restrictions (4) and (5) defined a subset of DISTINCT
**        sub-queries that were excluded from this optimization. Restriction 
**        (4) has since been expanded to exclude all DISTINCT subqueries.
**
................................................................................
  ** are processed - there is no mechanism to determine if the LEFT JOIN
  ** table should be all-NULL.
  **
  ** See also tickets #306, #350, and #3300.
  */
  if( (pSubitem->fg.jointype & JT_OUTER)!=0 ){
    isLeftJoin = 1;
    if( pSubSrc->nSrc>1 || isAgg ){
      return 0; /* Restriction (3) */
    }
  }
#ifdef SQLITE_EXTRA_IFNULLROW
  else if( iFrom>0 && !isAgg ){
    /* Setting isLeftJoin to -1 causes OP_IfNullRow opcodes to be generated for
    ** every reference to any result column from subquery in a join, even though

**
**   (2)  The subquery is not an aggregate or (2a) the outer query is not a join
**        and (2b) the outer query does not use subqueries other than the one
**        FROM-clause subquery that is a candidate for flattening.  (2b is
**        due to ticket [2f7170d73bf9abf80] from 2015-02-09.)
**
**   (3)  The subquery is not the right operand of a LEFT JOIN
**        or (a) the subquery is not itself a join and (b) the FROM clause
**        of the subquery does not contain a virtual table and (c) the 
**        outer query is not an aggregate.
**
**   (4)  The subquery is not DISTINCT.
**
**  (**)  At one point restrictions (4) and (5) defined a subset of DISTINCT
**        sub-queries that were excluded from this optimization. Restriction 
**        (4) has since been expanded to exclude all DISTINCT subqueries.
**
................................................................................
  ** are processed - there is no mechanism to determine if the LEFT JOIN
  ** table should be all-NULL.
  **
  ** See also tickets #306, #350, and #3300.
  */
  if( (pSubitem->fg.jointype & JT_OUTER)!=0 ){
    isLeftJoin = 1;
    if( pSubSrc->nSrc>1 || isAgg || IsVirtual(pSubSrc->a[0].pTab) ){
      return 0; /* Restriction (3) */
    }
  }
#ifdef SQLITE_EXTRA_IFNULLROW
  else if( iFrom>0 && !isAgg ){
    /* Setting isLeftJoin to -1 causes OP_IfNullRow opcodes to be generated for
    ** every reference to any result column from subquery in a join, even though

  ) ON tt.a = rrr
} {1 1 abc 2 {} {}}

do_execsql_test 3.2 {
  SELECT * FROM tt LEFT JOIN vt ON (vt MATCH 'abc')
} {1 abc 2 abc}






















finish_test

  ) ON tt.a = rrr
} {1 1 abc 2 {} {}}

do_execsql_test 3.2 {
  SELECT * FROM tt LEFT JOIN vt ON (vt MATCH 'abc')
} {1 abc 2 abc}

#-------------------------------------------------------------------------
# Test that queries of the form found in test case 4.2 use an automatic
# index to avoid running multiple fts queries.
#
do_execsql_test 4.1 {
  CREATE VIRTUAL TABLE ft4 USING fts3(x);
  CREATE TABLE t4(y, z);
  CREATE INDEX t4y ON t1(y);
}

do_eqp_test 4.2 {
  SELECT * FROM t4 LEFT JOIN (
      SELECT docid, * FROM ft4 WHERE ft4 MATCH ?
  ) AS rr ON t4.rowid=rr.docid 
  WHERE t4.y = ?;
} {
  1 0 0 {SCAN TABLE ft4 VIRTUAL TABLE INDEX 3:} 
  0 0 0 {SCAN TABLE t4}
  0 1 1 {SEARCH SUBQUERY 1 AS rr USING AUTOMATIC COVERING INDEX (docid=?)}
}

finish_test