SQLite

      }
      sqlite3ExprListDelete(db, pOrigRhs);
      if( pOrigLhs ){
        sqlite3ExprListDelete(db, pOrigLhs);
        pNew->pLeft->x.pList = pLhs;
      }
      pSelect->pEList = pRhs;
      pSelect->selId = ++pParse->nSelect; /* Req'd for SubrtnSig validity */
      if( pLhs && pLhs->nExpr==1 ){
        /* Take care here not to generate a TK_VECTOR containing only a
        ** single value. Since the parser never creates such a vector, some
        ** of the subroutines do not handle this case.  */
        Expr *p = pLhs->a[0].pExpr;
        pLhs->a[0].pExpr = 0;
        sqlite3ExprDelete(db, pNew->pLeft);

  SELECT * FROM v1 WHERE u IN w1
  UNION ALL
  SELECT * FROM v2 WHERE u IN w2
} {
  1 2 3 4 5 6
}

# 2024-11-20 https://sqlite.org/forum/forumpost/0b9ded2f8428ac00
#
# Bug in SubrtnSig logic.  If a SELECT statement is copied and the copy
# is subsequently modified, we need to change the Select.selId on the
# copy so that when the copy is used to generate code, the SubrtnSig
# logic won't try to substitute the original SELECT in place of the
# copy which is now different.
#
do_execsql_test 3.5 {
  DROP TABLE IF EXISTS t1;
  DROP TABLE IF EXISTS t2;
  CREATE TABLE t1 (a int UNIQUE);
  CREATE TABLE t2 (b int UNIQUE);
  INSERT INTO t1 VALUES (1);
  INSERT INTO t2 VALUES (1), (2);
  SELECT t1.a, t2.b FROM t1, t2 WHERE (t1.a, t2.b) = (1, 1);
} {1 1}
do_execsql_test 3.6 {
  SELECT t1.a, t2.b FROM t1, t2 WHERE (t1.a, t2.b) IN ((1, 1));
} {1 1}
do_execsql_test 3.7 {
  SELECT t1.a, t2.b FROM t1, t2 WHERE (t1.a, t2.b) = (1, 2);
} {1 2}
do_execsql_test 3.8 {
  SELECT t1.a, t2.b FROM t1, t2 WHERE (t1.a, t2.b) IN ((1, 2));
} {1 2}

finish_test