runningDifference WRONG RESULT with enable_optimize_predicate_expression #3885
Description
Connected to ClickHouse server version 18.16.0 revision 54412.
set enable_optimize_predicate_expression = 1
select n, z, changed from (
select n, z, runningDifferenceStartingWithFirstValue(n) as changed from (
select ts, n,z from system.one array join [1,3,4,5,6] as ts,
[1,2,2,2,1] as n, ['a', 'a', 'b', 'a', 'b'] as z
order by n, ts DESC)
) where changed = 0
┌─n─┬─z─┬─changed─┐
│ 2 │ b │ 0 │
└───┴───┴─────────┘
set enable_optimize_predicate_expression = 0
The same query
┌─n─┬─z─┬─changed─┐
│ 1 │ a │ 0 │
│ 2 │ b │ 0 │
│ 2 │ a │ 0 │
└───┴───┴─────────┘