BOOLEAN assert_true(BOOLEAN condition, VarcharLiteral errmsg)
When condition is true, return true. Otherwise throws an error with message errmsg. errmsg could only be Literal.
mysql> select assert_true(1, "wrong"); +------------------------------------------+ | assert_true(cast(1 as BOOLEAN), 'wrong') | +------------------------------------------+ | 1 | +------------------------------------------+ 1 row in set (0.12 sec) mysql> select assert_true(1, nullable("wrong")); ERROR 1105 (HY000): errCode = 2, detailMessage = assert_true only accept constant for 2nd argument mysql> select assert_true(0, "wrong"); ERROR 1105 (HY000): errCode = 2, detailMessage = (10.16.10.8)[INVALID_ARGUMENT][E33] wrong mysql> select assert_true(null, "wrong"); ERROR 1105 (HY000): errCode = 2, detailMessage = (10.16.10.8)[INVALID_ARGUMENT][E33] wrong
ASSERT_TRUE, ASSERT, TRUE