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如果我有兩個表job,employee。 我需要從作業中選擇所有,併爲每項作業添加員工數量。從多個表中選擇mysql的次數
認爲結果
job table
+-------------+-------------+
| id | name |
+-------------+-------------+
| 1 | Teacher |
+-------------+-------------+
| 2 | Engineer |
+-------------+-------------+
| 3 | Programmer |
+-------------+-------------+
employee table
+-------------+-------------+-------------+
| id | name | job_id |
+-------------+-------------+-------------+
| 1 | employee N | 1 |
+-------------+-------------+-------------+
| 2 | employee N | 2 |
+-------------+-------------+-------------+
| 3 | employee N | 3 |
+-------------+-------------+-------------+
| 4 | employee N | 1 |
+-------------+-------------+-------------+
| 5 | employee N | 3 |
+-------------+-------------+-------------+
| 6 | employee N | 1 |
+-------------+-------------+-------------+
我需要從作業的所有選擇和追加的員工數爲每個作業。
認爲結果
Result table
+-------------+-------------+--------------+
| id | name |employee count|
+-------------+-------------+--------------+
| 1 | Teacher | 3 |
+-------------+-------------+--------------+
| 2 | Engineer | 1 |
+-------------+-------------+--------------+
| 3 | Programmer | 2 |
+-------------+-------------+--------------+