fix: fix case when expr in db

[taozhi8833998]

• fix Error when expression with an array index is in a CASE expression #2434

[cmlee-accelins]

@taozhi8833998 I think array indexed functions could be in either the condition or the result of the case statement, for example:

SELECT CASE WHEN SPLIT('a-b', '-')[0] = 'a' THEN '1' ELSE '2' END FROM DUAL

and this looks like it only addresses the result in snowflake and postgres

[taozhi8833998]

@taozhi8833998 I think array indexed functions could be in either the condition or the result of the case statement, for example:

SELECT CASE WHEN SPLIT('a-b', '-')[0] = 'a' THEN '1' ELSE '2' END FROM DUAL

and this looks like it only addresses the result in snowflake and postgres

ok, support that, update the pr, add the test case