如何在SQL（STUCK）中合并多个WHERE

Question

How do i merge this 2 data together to get data like this

SELECT A.schlvl AS School, COUNT(DISTINCT A.name) AS NoOfChild ,SUM(B.cat_id=1) AS Picture 
FROM child AS A INNER JOIN
question AS B 
ON A.child_id=B.child_id
WHERE B.answer=0 AND B.cat_id=1
GROUP BY A.schlvl


SELECT COUNT(DISTINCT A.name) AS Gotitright ,SUM(B.cat_id=2) AS Letters
FROM child AS A INNER JOIN
question AS B 
ON A.child_id=B.child_id
WHERE B.answer = 0 AND B.cat_id = 2
GROUP BY A.schlvl

OR

Something like this, but i am stuck with this

SELECT A.schlvl AS School, COUNT(DISTINCT A.name WHERE B.answer=0 AND B.cat_id=1) AS Picture , COUNT(DISTINCT A.name WHERE B.answer=0 AND B.cat_id=2) AS Letters
FROM child AS A INNER JOIN
question AS B 
ON A.child_id=B.child_id
GROUP BY A.schlvl

Answer 1

From your query.

You can try to use IN in B.cat_id to get cat_id 1 or 2 in WHERE clause.

use Aggregate function condition let CASE WHEN in SUM function.

SELECT A.schlvl AS School, COUNT(DISTINCT CASE WHEN B.cat_id = 1 THEN A.name END) AS NoOfChild ,SUM(CASE WHEN B.cat_id IN (1,2) THEN 1 END) AS Picture 
FROM 
child AS A INNER JOIN question AS B ON A.child_id=B.child_id
WHERE B.answer=0 AND B.cat_id= in (1,2)
GROUP BY A.schlvl