[BUG] IF function does not work inside aggregation function

[penghuo]

What is the bug?
The following PPL query throw syntax error exception. ANTLR parse IF as keywordsCanBeId, instead of functionName.

source=tbl | stats sum(IF(a>10, 1, 0)) by group

[LantaoJin]

seems a bug in expression if(a>10, 1, 0). source=tbl | stats sum(IF(like(b, '%Hello%'), 1, 0)) by group works.