The string type operand will be converted to DOUBLE.
SELECT i FROM t WHERE i <= all {'11','12'};
i
=============
1
2
3
4
The string type operand will be converted to the date/time type.
SELECT s FROM t2;
s
======================
'01/01/2000'
'01/01/1999'
'01/01/1998'
SELECT s FROM t2 WHERE s <= ALL {date'02/02/1998',date'01/01/2000'};
s
======================
'01/01/1998'
If it is impossible to convert to the corresponding type, an error is returned.