Please help me write a SQL statementㅜ

MYINFO

ID(PK)/CmpID(FK)/NAME/POSITION/PhoneNumber

0/1 / Hong Gil-dong 1 / Employee / 010-1234-5678

1/ 1 / Hong Gil-dong 2 / Temple / 010-1234-5678

2/2 / Hong Gil-dong 3 / Temple / 010-1234-5678

3/3 / Hong Gil-dong 4 / Temple / 010-1234-5678

4/3 / Hong Gil-dong 5 / Employee / 010-1234-5678

5/4 / Hong Gil-dong 6 / Employee / 010-1234-5678

6/5 / Hong Gil-dong 7 / Temple / 010-1234-5678

CMPINFO

ID(PK)/CmpName/OfficeName

1 / Gogoseon Co., Ltd. / Korea 1

2 / Gogoseon Co., Ltd. / Korea 2

3 / Gogoseon Co., Ltd. / Korea 3

4/Hanra Co., Ltd. / China 1

5 / Hanara / China 2

ex)Hong Gil-dong 4-ga finds all the employees of his company regardless of the office. = CmpName finds everyone who is "(Go Chosun Co., Ltd.)

Results

Hong Gil-dong 1

Hong Gil-dong 2

Hong Gil-dong 3

Hong Gil-dong 4

Hong Gil-dong 5

I have to JOIN, but I don't know what to do.<

database sql join

2022-09-21 17:12

1 Answers

I think I can solve it easily with SubQuery rather than JOIN I wrote the query statement for the ex you suggested.

SELECT my.NAME
FROM MYINFO as my, CMPINFO as cmp
WHERE my.CmpID = cmp.ID AND 
          cmp.CmpName =
                    (SELECT cmp.CmpName
                     FROM MYINFO as my, CMPINFO as cmp
                     WHERE my.NAME="Hong Gil-dong 4" AND my.CmpID=cmp.ID)

2022-09-21 17:12

If you have any answers or tips

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