Window function's output order is wrong

[winoros]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?
   If possible, provide a recipe for reproducing the error.

CREATE TABLE `t1` (
  `id` int(11) DEFAULT NULL,
  `sex` char(1) DEFAULT NULL
);
insert into t1 values(1, 'F'), (2, 'M');
SELECT NTILE(2) OVER (ORDER BY sex) FROM t1 ORDER BY id+2 DESC;

2. What did you expect to see?

execute successfully.

3. What did you see instead?

panicked

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

[winoros]

After some investigation, when reading Int value, the column reached to places where stores Char.

[zz-jason]

Please also post the panic stack in the What did you see instead section

[winoros]

@zz-jason

[2019/03/19 16:53:50.686 +08:00] [WARN] [builder.go:1095] ["build proj exec"] ["column indices"="[0 1 2]"] [columns="[test.t1.sex test.t1.id 5_window_3]"]
[2019/03/19 16:53:50.686 +08:00] [WARN] [builder.go:1095] ["build proj exec"] ["column indices"="[2]"] [columns="[ntile(2) over (order by sex)]"]
[2019/03/19 16:53:50.687 +08:00] [WARN] [row.go:58] ["column data"] ["bytes data"="[70 70 70 77 77]"] ["byte len"=5] ["self len"=7] ["row num"=7] ["all col byte len"="[56,5,56]"]

From the schema, the three column of the projection should be char, int, int. But from the actual data in chunk, the order is int, char, int.
The cause of panic is the output wrong order. So panic stack is useless.

[winoros]

After checking, fixed by #10452