Question

I would like to know if there is a way to simplify the following SQL statement. This is my table.

| SID | name | l1 | l2 | sch |
|  1  | john |    |    | sch |
|  2  | mary | l1 |    |     |
|  3  | zack | l1 | l2 |     |
|  4  | paul | l1 | l2 | sch |

Either l1 or l2 is filled, or both can be filled

Not every ‘sch’ has a value

What I do is to calculate a daily summary table, but I do it via PHP, I am wondering if it can be done just using SQL. So eg,

- Total count (This is just count(name))
- Count(sch)
- If !empty (l1) OR !empty (l2) THEN l + 1

So now, based on the above

 Total count = 4
 count(sch) = 2
 count(l1 || l2) = 3

Can it be done in SQL?

Answer 1

select count(name) name_count,
       count(coalesce(nullif(l1,''), nullif(l2,''))) l1_or_l2_count,
       count(sch) sch_count
  from your_table;