SET convert_query_to_cnf = 1; SET optimize_using_constraints = 1; SET optimize_move_to_prewhere = 1; SET optimize_substitute_columns = 1; SET optimize_append_index = 1; DROP TABLE IF EXISTS column_swap_test_test; CREATE TABLE column_swap_test_test (i Int64, a String, b UInt64, CONSTRAINT c1 ASSUME b = cityHash64(a)) ENGINE = MergeTree() ORDER BY i; INSERT INTO column_swap_test_test VALUES (1, 'cat', 1), (2, 'dog', 2); INSERT INTO column_swap_test_test SELECT number AS i, format('test {} kek {}', toString(number), toString(number + 10)) AS a, 1 AS b FROM system.numbers LIMIT 1000000; EXPLAIN SYNTAX SELECT cityHash64(a) + 10, b + 3 FROM column_swap_test_test WHERE cityHash64(a) = 1; EXPLAIN SYNTAX SELECT cityHash64(a) + 10, b + 3 FROM column_swap_test_test WHERE cityHash64(a) = 0; EXPLAIN SYNTAX SELECT cityHash64(a) + 10, b + 3 FROM column_swap_test_test WHERE b = 0; EXPLAIN SYNTAX SELECT cityHash64(a) + 10, b + 3 FROM column_swap_test_test WHERE b = 1; EXPLAIN SYNTAX SELECT cityHash64(a) + 10 FROM column_swap_test_test WHERE cityHash64(a) = 0; EXPLAIN SYNTAX SELECT cityHash64(a) + 10, a FROM column_swap_test_test WHERE cityHash64(a) = 0; EXPLAIN SYNTAX SELECT b + 10, a FROM column_swap_test_test WHERE b = 0; DROP TABLE column_swap_test_test; CREATE TABLE column_swap_test_test (i Int64, a String, b String, CONSTRAINT c1 ASSUME a = substring(reverse(b), 1, 1)) ENGINE = MergeTree() ORDER BY i; INSERT INTO column_swap_test_test SELECT number AS i, toString(number) AS a, format('test {} kek {}', toString(number), toString(number + 10)) b FROM system.numbers LIMIT 1000000; EXPLAIN SYNTAX SELECT substring(reverse(b), 1, 1), a FROM column_swap_test_test WHERE a = 'c'; EXPLAIN SYNTAX SELECT substring(reverse(b), 1, 1), a FROM column_swap_test_test WHERE substring(reverse(b), 1, 1) = 'c'; EXPLAIN SYNTAX SELECT substring(reverse(b), 1, 1) AS t1, a AS t2 FROM column_swap_test_test WHERE substring(reverse(b), 1, 1) = 'c'; EXPLAIN SYNTAX SELECT substring(reverse(b), 1, 1) FROM column_swap_test_test WHERE substring(reverse(b), 1, 1) = 'c'; DROP TABLE column_swap_test_test; DROP TABLE IF EXISTS t_bad_constraint; CREATE TABLE t_bad_constraint(a UInt32, s String, CONSTRAINT c1 ASSUME a = toUInt32(s)) ENGINE = MergeTree ORDER BY tuple(); INSERT INTO t_bad_constraint SELECT number, randomPrintableASCII(100) FROM numbers(10000); EXPLAIN SYNTAX SELECT a FROM t_bad_constraint; DROP TABLE t_bad_constraint;