# 2020-12-22
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is flattening UNION ALL sub-queries.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix unionall2

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b);
  CREATE TABLE t2(c, d);

  CREATE VIEW v1 AS SELECT * FROM t1, t2;
  CREATE VIEW v2 AS SELECT * FROM t1, t2;

  CREATE VIEW vA AS
    SELECT * FROM v1, (
      SELECT * FROM t1 LEFT JOIN t2 ON (a=c)
    )
    UNION ALL
    SELECT * FROM v1, v2
}

do_execsql_test 1.1 {
  SELECT 1 FROM vA, vA, vA, vA, vA, vA, vA, vA, vA, vA
}

#-------------------------------------------------------------------------

do_execsql_test 2.1 {
  CREATE TABLE y1(a INTEGER, b);
  CREATE TABLE y2(c INTEGER, d);

  CREATE TABLE x3_a(a INTEGER PRIMARY KEY, b TEXT);
  CREATE TABLE x3_b(c INTEGER PRIMARY KEY, d TEXT);
}

do_execsql_test 2.2 {

  SELECT * FROM y1 CROSS JOIN y2 WHERE y1.a=y2.c AND y2.c IN (
    SELECT a FROM x3_a UNION ALL
    SELECT c FROM x3_b ORDER BY 1
  )
}

#-------------------------------------------------------------------------
# https://sqlite.org/bugs/forumpost/b6e0cf3df3
#
reset_db

do_execsql_test 3.0 {
  CREATE TABLE t0(c0);
  CREATE TABLE t1(c0);
  INSERT INTO t0 VALUES (NULL);
}

do_execsql_test 3.1 {
  SELECT 5 FROM t0 WHERE (SELECT 0) 
  UNION ALL 
  SELECT 7 FROM t1 RIGHT JOIN t0 ON 0
} 7

do_execsql_test 3.2 {
  SELECT * FROM (
    SELECT 5 FROM t0 WHERE (SELECT 0) 
    UNION ALL 
    SELECT 7 FROM t1 RIGHT JOIN t0 ON 0
  );
} {7}

do_execsql_test 3.3 {
  SELECT * FROM (
    SELECT c0 FROM t0 
    UNION ALL 
    SELECT a.c0 FROM t0 AS a RIGHT JOIN t0 AS b ON 0
  )
} {{} {}}

do_execsql_test 3.4 {
  SELECT * FROM (
    SELECT c0 FROM t0 
    UNION ALL 
    SELECT a.c0 FROM t0 AS a RIGHT JOIN t0 AS b ON 0
  ) WHERE abs(c0)
} {}

do_execsql_test 3.5 {
  CREATE TABLE t2(a, x);  CREATE INDEX t2x ON t2(x);
  CREATE TABLE t3(b, y);  CREATE INDEX t3y ON t3(y);
  CREATE TABLE t4(c, d);  CREATE INDEX t4d ON t4(d);
}

do_eqp_test 3.6 {
  SELECT * FROM t4 CROSS JOIN (
    SELECT a, x FROM t2 UNION ALL SELECT b, y FROM t3
  ) AS s WHERE s.a=t4.d AND s.x=5;
} {
  QUERY PLAN
  `--COMPOUND QUERY
     |--LEFT-MOST SUBQUERY
     |  |--SCAN t4
     |  `--SEARCH t2 USING INDEX t2x (x=?)
     `--UNION ALL
        |--SCAN t4
        `--SEARCH t3 USING INDEX t3y (y=?)
}


finish_test