我正在嘗試將數據從table1填充到table2。我的sql查詢是否正確？

Question

表格1

 EID     EMPLOYEE_NAME       DESIGNATION               REPORTING_MANAGER    FLAG
    1        TIM COOK            CEO                   Null                 Null
    2        MILLER              CTO                   TIM COOK             Null
    3        BRAD                COO                   TIM COOK             Null
    4        WILLIAM             HRD                   TIM COOK             Null
    5        JOHN                TECH MANAGER(DEV)     WILLIAM              Null
    6        WALLACE             TECH MANAGER(TEST)    WILLIAM              Null
    7        SUNDAR              SWIFT DEV             JOHN                 Null
    8        PETER               SWIFT DEV             JOHN                 Null
    9        STEVE               TEST ENGINEER         WALLACE              Null

表2

 EID     EMPLOYEE_NAME      REPORTING_MANAGER_ID

我想生成類似下面的內容

EID     EMPLOYEE_NAME      REPORTING_MANAGER_ID
    1        TIM COOK          Null
    2        MILLER            1
    3        BRAD              1
    4        WILLIAM           1
    5        JOHN              4
    6        WALLACE           4
    7        SUNDAR            5
    8        PETER             5
    9        STEVE             6

我嘗試了以下查詢，它成功運行但不在table2中插入數據。

---

INSERT INTO table2 (
    E_ID
    ,EMPLOYEE_NAME
    ,REPORTING_MANAGER_ID
    )
SELECT e.E_ID
    ,e.EMPLOYEE_NAME
    ,rm.E_ID AS REPORTING_MANAGER_ID
FROM table1 e
LEFT JOIN table1 rm ON rm.EMPLOYEE_NAME = e.REPORTING_MANAGER
WHERE e.FLAG = NULL

---

有人幫助我

Answer 1

INSERT INTO table2 (E_ID,EMPLOYEE_NAME,REPORTING_MANAGER_ID) 
 SELECT e.E_ID , e.EMPLOYEE_NAME, rm.E_ID 
 FROM table1 e 
 LEFT JOIN table1 rm ON rm.EMPLOYEE_NAME = e.REPORTING_MANAGER 
 WHERE e.FLAG is NULL

如果將列與null進行比較，則返回null ，這將不會從select語句返回任何行。 使用is null 。

Answer 2

下面提到的兩個查詢將給出您需要的結果。

- 使用SubQuery

INSERT INTO table2（EID，EMPLOYEE_NAME，REPORTING_MANAGER_ID）SELECT t1.EID t1.Employee_Name，（SELECT EID FROM table1 t2 WHERE t1.EMPLOYEE_NAME = t2.REPORTING_MANAGER）AS REPORTING_MANAGER_ID FROM table1 t1

- 使用加入條件

INSERT INTO table2（EID，EMPLOYEE_NAME，REPORTING_MANAGER_ID）SELECT t1.EID，t1.EMPLOYEE_NAME，t2.REPORTING_MANAGER FROM table1 t1 LEFT OUTER JOIN table1 t2 ON t1.EMPLOYEE_NAME = t2.REPORTING_MANAGER