SQLite

** CREATE TABLE t1(a);
** SELECT * FROM t1 WHERE a;
** SELECT a AS b FROM t1 WHERE b;
** SELECT * FROM t1 WHERE (select a from t1);
*/
char sqlite3ExprAffinity(const Expr *pExpr){
  int op;
  while( ExprHasProperty(pExpr, EP_Skip|EP_IfNullRow) ){
    assert( pExpr->op==TK_COLLATE || pExpr->op==TK_IF_NULL_ROW );
    pExpr = pExpr->pLeft;
    assert( pExpr!=0 );
  }
  op = pExpr->op;
  if( op==TK_SELECT ){
    assert( pExpr->flags&EP_xIsSelect );

}

/*
** Skip over any TK_COLLATE operators.
*/
Expr *sqlite3ExprSkipCollate(Expr *pExpr){
  while( pExpr && ExprHasProperty(pExpr, EP_Skip) ){
    assert( pExpr->op==TK_COLLATE );
    pExpr = pExpr->pLeft;
  }   
  return pExpr;
}

/*
** Skip over any TK_COLLATE operators and/or any unlikely()
** or likelihood() or likely() functions at the root of an
** expression.
*/
Expr *sqlite3ExprSkipCollateAndLikely(Expr *pExpr){
  while( pExpr && ExprHasProperty(pExpr, EP_Skip|EP_Unlikely) ){
    if( ExprHasProperty(pExpr, EP_Unlikely) ){
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      assert( pExpr->x.pList->nExpr>0 );
      assert( pExpr->op==TK_FUNCTION );
      pExpr = pExpr->x.pList->a[0].pExpr;
    }else{
      assert( pExpr->op==TK_COLLATE );
      pExpr = pExpr->pLeft;
    }
  }   
  return pExpr;
}

/*

      }else{
        sqlite3 *db = pSubst->pParse->db;
        if( pSubst->isLeftJoin && pCopy->op!=TK_COLUMN ){
          memset(&ifNullRow, 0, sizeof(ifNullRow));
          ifNullRow.op = TK_IF_NULL_ROW;
          ifNullRow.pLeft = pCopy;
          ifNullRow.iTable = pSubst->iNewTable;
          ifNullRow.flags = EP_IfNullRow;
          pCopy = &ifNullRow;
        }
        testcase( ExprHasProperty(pCopy, EP_Subquery) );
        pNew = sqlite3ExprDup(db, pCopy, 0);
        if( pNew && pSubst->isLeftJoin ){
          ExprSetProperty(pNew, EP_CanBeNull);
        }

#define EP_IntValue   0x000400 /* Integer value contained in u.iValue */
#define EP_xIsSelect  0x000800 /* x.pSelect is valid (otherwise x.pList is) */
#define EP_Skip       0x001000 /* Operator does not contribute to affinity */
#define EP_Reduced    0x002000 /* Expr struct EXPR_REDUCEDSIZE bytes only */
#define EP_TokenOnly  0x004000 /* Expr struct EXPR_TOKENONLYSIZE bytes only */
#define EP_Win        0x008000 /* Contains window functions */
#define EP_MemToken   0x010000 /* Need to sqlite3DbFree() Expr.zToken */
#define EP_IfNullRow  0x020000 /* The TK_IF_NULL_ROW opcode */
#define EP_Unlikely   0x040000 /* unlikely() or likelihood() function */
#define EP_ConstFunc  0x080000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */
#define EP_CanBeNull  0x100000 /* Can be null despite NOT NULL constraint */
#define EP_Subquery   0x200000 /* Tree contains a TK_SELECT operator */
#define EP_Alias      0x400000 /* Is an alias for a result set column */
#define EP_Leaf       0x800000 /* Expr.pLeft, .pRight, .u.pSelect all NULL */
#define EP_WinFunc   0x1000000 /* TK_FUNCTION with Expr.y.pWin set */

do_execsql_test 8.1 {
  SELECT * FROM t0 LEFT JOIN t1 
  WHERE (t1.c0 BETWEEN 0 AND 0) > ('' AND t0.c0);
}

#-------------------------------------------------------------------------
# Ticket [45f4bf4eb] reported by Manuel Rigger (2020-04-25)
#
# Follow up error reported by Eric Speckman on the SQLite forum
# https://sqlite.org/forum/info/c49496d24d35bd7c (2020-08-19)
#
reset_db
do_execsql_test 9.0 {
  CREATE TABLE t0(c0 INT);
  CREATE VIEW v0(c0) AS SELECT CAST(t0.c0 AS INTEGER) FROM t0;
  INSERT INTO t0(c0) VALUES (0);
}

  SELECT * FROM t0 LEFT JOIN v0 ON v0.c0 >= '0';
} {0 0}

do_execsql_test 9.5 {
  SELECT * FROM t0 LEFT JOIN v0 ON v0.c0 >= '0' WHERE TRUE 
  UNION SELECT 0,0 WHERE 0; 
} {0 0}

do_execsql_test 9.10 {
  CREATE TABLE t1 (aaa);
  INSERT INTO t1 VALUES(23456);
  CREATE TABLE t2(bbb);
  CREATE VIEW v2(ccc) AS SELECT bbb IS 1234 FROM t2;
  SELECT ccc, ccc IS NULL AS ddd FROM t1 LEFT JOIN v2;
} {{} 1}
optimization_control db query-flattener 0
do_execsql_test 9.11 {
  SELECT ccc, ccc IS NULL AS ddd FROM t1 LEFT JOIN v2;
} {{} 1}


finish_test