how to fix sql query?

Question

In this noti_card_data my DB schema

  id      | date  |        cmd  |     mbrNo
--------------------------------------------
  1        2020-04-01      success    1
  2        2020-04-29      fail       -

I Want result

  id      | date  |        cmd  |     mbrNo
--------------------------------------------
  1        2020-04-01      success    1

But, sending a query like this results.

SELECT * FROM noti_card_data WHERE mbrNo = '1'  OR mbrNo = '-'  AND cmd ='success' 



 id      | date  |        cmd  |     mbrNo
--------------------------------------------
  1        2020-04-01      success    1
  2        2020-04-29      fail       -

How to fix my query?

Answer 1

Try the following, here is the demo .

SELECT * 
FROM noti_card_data 
WHERE (mbrNo = '1'
OR mbrNo = '-')
AND cmd ='success'

Output:

| id  | date       | cmd     | mbrNo |
| --- | ---------- | ------- | ----- |
| 1   | 2020-04-01 | success | 1     |

Answer 2

Instead of

mbrNo = '1'  OR mbrNo = '-'

you can say

mbrNo IN ('1', '-')

Although those two expressions are identical, the change would have coincidentally fixed your problem.

The real "problem" is

a OR b AND c   means   a OR (b AND c)

but you wanted

                       (a OR b) AND c

See "precedence of operators".