i have problem with my SQL syntax but i still a novice programmer so i don't know what the error message meant.

here's my code:

```
set @csum = 0;
select b.nama as divisi, a.nama, a.tgl, a.act, a.L_mulai, a.L_selesai, a.tot_jam, a.ket, (CASE WHEN a.act = 'lembur' THEN @csum = @csum + a.tot_jam ELSE @csum = @csum - a.tot_jam ) as `total jam`
FROM tbl_rkp_lemburtj AS a
LEFT JOIN tbl_bagian AS b ON a.Divisi = b.id
WHERE a.nama = 'Rofiq'
order by a.id;

```

please tell me what must i do to correct it. 

here's the error message i got:

```
You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ') as `total jam` FROM tbl_rkp_lemburtj AS a LEFT JOIN tbl_bagian AS b ON a.Div' at line 1

```

i expect the result to be like this:
[![enter image description here](https://i.stack.imgur.com/ooPAS.png)](https://i.stack.imgur.com/ooPAS.png)

column total jam is running total of tot\_jam with parameter **if act is lembur than add, else if act is tj then subtract**