全选，除非MYSQL中的特定单元格值

Question

I'm stuck and I can't figure it out, so I would appreciate any help.

At this point i have table journal which consists of columns:

id | name | type(int) | classification | data      | journalUser | start_date(default NULL)
1  |  John  |  1      |  2             |  data123  |  1          |  10-11-2019
2  |  Peter |  2      |  2             |  data123  |  1          |  10-11-2019
3  |  Ash   |  2      |  2             |  data123  |  NULL       |  NULL
4  |  BUBU  |  2      |  2             |  data123  |  3          |  10-11-2019

I want to make query where I select all, but with exceptions, for example: SELECT * from journal, but if column type = 2, than select this row too if journalUser = 1 AND second check if column type = 2 and start_date IS NULL, than select this row too.

As the result, from table above, from query I wan to get result

id | name | type(int) | classification | data | journalUser | start_date(default NULL)
1  |  John  |  1  |  2  |  data123  |  1  |  10-11-2019
2  |  Peter |  2  |  2  |  data123  |  1  |  10-11-2019
3  |  Ash   |  2  |  2  |  data123  |  NULL  |  NULL

Answer 1

That's a specific case when the type is 2.

To get the rows with type = 2 along with either (considering the expected output) journalUser = 1 or start_date = null , this can be written this way :

type = 2 AND (journalUser = 1 OR start_date IS NULL)

To make sure you have others type too, you can add an OR condition such as :

OR type <> 2.

This will give this query :

SELECT *
FROM journal
WHERE (type = 2 AND (journalUser = 1 OR start_date IS NULL))
    OR type <> 2