# name: test/sql/optimizer/expression/test_cse.test
# description: Test queries involving Common SubExpressions
# group: [expression]

statement ok
SET default_null_order='nulls_first';

statement ok
PRAGMA enable_verification

statement ok
create table test(a integer);

statement ok
insert into test values (42);

# single CSE
query I
SELECT (a*2)+(a*2) FROM test
----
168

# multiple CSEs
query I
SELECT (a*2)+(a*2)+(a*2)+(a*2)+(a*2) FROM test
----
420

# use the actual columns still
query II
SELECT (a*2)+(a*2)+(a*2)+(a*2)+(a*2), a FROM test
----
420	42

# CSE in aggregates
query I
SELECT SUM((a*2)+(a*2)+(a*2)+(a*2)+(a*2)) FROM test
----
420

# also with group by clause
query II
SELECT a, SUM((a*2)+(a*2)+(a*2)+(a*2)+(a*2)) FROM test GROUP BY a
----
42	420


# CSE in WHERE clause
query I
SELECT * FROM test WHERE ((a*2)+(a*2))>100
----
42

# multiple CSE in WHERE clause
query I
SELECT * FROM test WHERE ((a*2)+(a*2)+(a*2)+(a*2)+(a*2))>400
----
42

# Strings and NULL values
statement ok
create table test2(a VARCHAR);

statement ok
insert into test2 values ('hello'), ('world'), (NULL);

# single CSE in projection
query T
SELECT substring(a, 1, 3)=substring(a, 1, 3) FROM test2 ORDER BY 1
----
NULL
1
1

# now with GROUP BY clause
query T
SELECT substring(a, 1, 3)=substring(a, 1, 3) AS b FROM test2 GROUP BY b ORDER BY b
----
NULL
1