79ff0ad2a4
This commit will add a new sql mode named MODE_PIPES_AS_CONCAT:
Description:
1、If this mode is active, '||' will be handled different from the original way ('||' and 'or' are seen as the same symbols in Doris) that it can be used to concat two exps and returns a new string. For example, 'a' || 'b' = 'ab' and 1 || 0 = '10'.
2. User can active this mode by "SET sql_mode = PIPES_AS_CONCAT", and deactive it by "SET sql_mode = '' ".