mysql在一个查询中有多个计数

Question

SELECT SUM( CASE WHEN is_half = 1 THEN 1 ELSE 0 END ) halfCount, SUM( CASE 
WHEN is_half = 0 THEN 1 ELSE 0 END ) totalCount FROM employee_leave WHERE 
YEAR(leave_date_from) = YEAR(CURRENT_DATE()) AND employee_id="EMP12" AND 
leave_status=1

With this query I am getting results as(If there are no values):

halfCount | totalCount
NULL      | NULL

How can I get 0 instead of NULL?

Desired output:

halfCount | totalCount
0         | 0

Answer 1

Assuming your query is correct, you can use COALESCE to change null into 0 (or any other number)

SELECT COALESCE(SUM( CASE WHEN is_half = 1 THEN 1 ELSE 0 END ), 0) as 'halfCount',
COALESCE(SUM( CASE WHEN is_half = 0 THEN 1 ELSE 0 END ), 0) as 'totalCount'
FROM employee_leave
WHERE YEAR(leave_date_from) = YEAR(CURRENT_DATE()
     AND employee_id="EMP12"
     AND leave_status=1

I'm not really sure if this is error-free, as I can't test it in my machine, but that is how to use COALESCE

Answer 2

try this

SELECT IFNULL(SUM( CASE WHEN is_half = 1 THEN 1 ELSE 0 END ),0) halfCount, IFNULL(SUM( CASE 
WHEN is_half = 0 THEN 1 ELSE 0 END ),0) totalCount FROM employee_leave WHERE 
YEAR(leave_date_from) = YEAR(CURRENT_DATE()) AND employee_id="EMP12" AND 
leave_status=1