MySQL 查询、子查询、distinct、count、

Question

Employees table

Name.	New.
Shadab.	Yes
Ali.	No
Shadab.	Yes

Results

Name.	New(Yes).	New(No)
Shadab.	2.	0
Ali.	.	1

How can get this result from Employees Table? Using MySQL.

Just count Yes and No of New Column.

Answer 1

SELECT DISTINCT
    a.name, 
    coalesce(yes.numbers, 0), 
    coalesce(no.numbers, 0) 
FROM employees AS a
    LEFT JOIN (SELECT name, count(name) AS numbers FROM employees WHERE new = 'Yes' GROUP BY name) AS yes ON (a.name = yes.name)
    LEFT JOIN (SELECT name, count(name) AS numbers FROM employees WHERE new = 'No' GROUP BY name) AS no ON (a.name = no.name)

or with SUM and IF:

SELECT
    name,
    SUM(IF(new = 'Yes', 1, 0)) as yes_num,
    SUM(IF(new = 'No', 1, 0)) as no_num
FROM employees
GROUP BY name

Answer 2

here you can check the result

Here is your required Query:

SELECT 
Name,
SUM(CASE WHEN New='Yes' THEN 1 ELSE 0 END) as NEW_Yes,
SUM(CASE WHEN New!='Yes' THEN 1 ELSE 0 END) as NEW_No 
FROM `employees` 
GROUP BY Name