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Comment:Fix the sqliteExprImpliesExpr() routine so that it recognizes that "(NULL IS FALSE) IS FALSE" doe not imply "NULL NOT NULL". Ticket [9080b6227fabb466]
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SHA3-256: da01ba4fa47c6508b31533ccd769e637af04bd37f51463372fbc6c848d892a4d
User & Date: drh 2019-08-10 15:06:03
Original Comment: Fix the sqliteExprImpliesExpr() routine so that it recognizes that "(NULL IS FALSE) IS FALSE" doe not implie "NULL NOT NULL". Ticket [9080b6227fabb466]
Context
2019-08-12
00:08
Validate the type, name, and tbl_name fields of the sqlite_master table when loading the schema, unless writable_schema is engaged. (check-in: 724f4df9 user: drh tags: trunk)
2019-08-10
15:06
Fix the sqliteExprImpliesExpr() routine so that it recognizes that "(NULL IS FALSE) IS FALSE" doe not imply "NULL NOT NULL". Ticket [9080b6227fabb466] (check-in: da01ba4f user: drh tags: trunk)
14:35
Add extra test cases related to the previous commit. (check-in: 3c690b2b user: dan tags: trunk)
Changes
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Changes to src/expr.c.

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  Expr *p,            /* The expression to be checked */
  Expr *pNN,          /* The expression that is NOT NULL */
  int iTab,           /* Table being evaluated */
  int seenNot         /* True if p is an operand of NOT */
){
  assert( p );
  assert( pNN );
  if( sqlite3ExprCompare(pParse, p, pNN, iTab)==0 ) return 1;


  switch( p->op ){
    case TK_IN: {
      if( seenNot && ExprHasProperty(p, EP_xIsSelect) ) return 0;
      assert( ExprHasProperty(p,EP_xIsSelect)
           || (p->x.pList!=0 && p->x.pList->nExpr>0) );
      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, seenNot);
    }








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  Expr *p,            /* The expression to be checked */
  Expr *pNN,          /* The expression that is NOT NULL */
  int iTab,           /* Table being evaluated */
  int seenNot         /* True if p is an operand of NOT */
){
  assert( p );
  assert( pNN );
  if( sqlite3ExprCompare(pParse, p, pNN, iTab)==0 ){
    return pNN->op!=TK_NULL;
  }
  switch( p->op ){
    case TK_IN: {
      if( seenNot && ExprHasProperty(p, EP_xIsSelect) ) return 0;
      assert( ExprHasProperty(p,EP_xIsSelect)
           || (p->x.pList!=0 && p->x.pList->nExpr>0) );
      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, seenNot);
    }
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Changes to test/indexexpr1.test.

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  INSERT INTO t1 VALUES('1234',0),('001234',2),('01234',1);
  SELECT b FROM t1 WHERE lower(a)='1234' ORDER BY +b;
} {0 1 2 3}
do_execsql_test indexexpr-1620 {
  SELECT b FROM t1 WHERE lower(a)='01234' ORDER BY +b;
} {}













finish_test








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  INSERT INTO t1 VALUES('1234',0),('001234',2),('01234',1);
  SELECT b FROM t1 WHERE lower(a)='1234' ORDER BY +b;
} {0 1 2 3}
do_execsql_test indexexpr-1620 {
  SELECT b FROM t1 WHERE lower(a)='01234' ORDER BY +b;
} {}

# 2019-08-09 https://www.sqlite.org/src/info/9080b6227fabb466
# ExprImpliesExpr theorem prover bug:
# "(NULL IS FALSE) IS FALSE" does not imply "NULL IS NULL"
#
do_execsql_test indexexpr-1700 {
  DROP TABLE IF EXISTS t0;
  CREATE TABLE t0(c0);
  INSERT INTO t0(c0) VALUES (0);
  CREATE INDEX i0 ON t0(NULL > c0) WHERE (NULL NOT NULL);
  SELECT * FROM t0 WHERE ((NULL IS FALSE) IS FALSE);
} {0}

finish_test