What is the difference between these: ``` SELECT id FROM t1 WHERE x LIKE 'abc%%' ESCAPE '%'; ``` and ``` SELECT id FROM t1 WHERE x LIKE 'abc%%'; ``` and ``` SELECT id FROM t1 WHERE x LIKE 'abc%'; ``` I'm pretty sure the last one is a wildcard search, that (I assume) matches anything like the regular expression "abc.*". What match string expressed as a regular expression do the first two selects find?