Employees 桌子| 姓名。 | 新的。 |
|---|---|
| 沙达布。 | 是的 |
| 但。 | 不 |
| 沙达布。 | 是的 |
| 姓名。 | 新的（是）。 | 新品(否) |
|---|---|---|
| 沙达布。 | 2. | 0 |
| 但。 | . | 1 |
如何从Employees表中得到这个结果？使用 MySQL。
算了算Yes和No中New柱。
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)
或使用 SUM 和 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
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