SQLite

  /* Analyze all of the subexpressions. */
  sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC);
  if( pSelect && pSelect->pLimit ){
    sqlite3WhereAddLimit(&pWInfo->sWC, pSelect);
  }
  if( pParse->nErr ) goto whereBeginError;

  /* The False-WHERE-Term-Bypass optimization:
  **
  ** If there are WHERE terms that are false, then no rows will be output,
  ** so skip over all of the code generated here.
  **
  ** Conditions:
  **
  **   (1)  The WHERE term must not refer to any tables in the join.
  **   (2)  The term must not come from an ON clause on the
  **        right-hand side of a LEFT or FULL JOIN.
  **   (3)  The term must not come from an ON clause, or there must be
  **        no RIGHT or FULL OUTER joins in pTabList.
  **   (4)  If the expression contains non-deterministic functions
  **        that are not within a sub-select. This is not required
  **        for correctness but rather to preserves SQLite's legacy
  **        behaviour in the following two cases:
  **
  **          WHERE random()>0;           -- eval random() once per row
  **          WHERE (SELECT random())>0;  -- eval random() just once overall
  **
  ** Note that the Where term need not be a constant in order for this
  ** optimization to apply, though it does need to be constant relative to
  ** the current subquery (condition 1).  The term might include variables
  ** from outer queries so that the value of the term changes from one
  ** invocation of the current subquery to the next.
  */
  for(ii=0; ii<sWLB.pWC->nBase; ii++){
    WhereTerm *pT = &sWLB.pWC->a[ii];  /* A term of the WHERE clause */
    Expr *pX;                          /* The expression of pT */
    int ltoj;                          /* Left table of the join */
    if( pT->wtFlags & TERM_VIRTUAL ) continue;
    pX = pT->pExpr;
    assert( pX!=0 );
    assert( pT->prereqAll!=0 || !ExprHasProperty(pX, EP_OuterON) );
    if( pT->prereqAll==0                           /* Conditions (1) and (2) */
     && (nTabList==0 || exprIsDeterministic(pX))   /* Condition (4) */
     && !(ExprHasProperty(pX, EP_InnerON)          /* Condition (3) */
          && (pTabList->a[0].fg.jointype & JT_LTORJ)!=0 )
    ){
      sqlite3ExprIfFalse(pParse, pX, pWInfo->iBreak, SQLITE_JUMPIFNULL);
      pT->wtFlags |= TERM_CODED;
    }
  }

  if( wctrlFlags & WHERE_WANT_DISTINCT ){
    if( OptimizationDisabled(db, SQLITE_DistinctOpt) ){
      /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via

  CREATE INDEX i1 ON t1( (d IS NULL), d );
}

do_execsql_test 4.4 {
  SELECT (d IS NULL) FROM t1 RIGHT JOIN t2 ON (j=33);
} {1}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 5.0 {
  CREATE TABLE t0(w);
  CREATE TABLE t1(x);
  CREATE TABLE t2(y);
  CREATE TABLE t3(z);
  INSERT INTO t3 VALUES('t3val');
}

do_execsql_test 5.1 {
  SELECT * FROM t1 INNER JOIN t2 ON (0) RIGHT OUTER JOIN t3;
} {{} {} t3val}

do_execsql_test 5.2 {
  SELECT * FROM t1 INNER JOIN t2 ON (0) FULL OUTER JOIN t3;
} {{} {} t3val}

do_execsql_test 5.3 {
  SELECT * FROM t3 LEFT JOIN t2 ON (0);
} {t3val {}}

do_execsql_test 5.4 {
  SELECT * FROM t0 RIGHT JOIN t1 INNER JOIN t2 ON (0) RIGHT JOIN t3
} {{} {} {} t3val}

do_execsql_test 5.5 {
  SELECT * FROM t0 RIGHT JOIN t1 INNER JOIN t2 ON (0)
} {}

finish_test