[mysql] delete / left join

DELETE g5_shop_cart
FROM g5_shop_cart LEFT JOIN g5_shop_order ON g5_shop_cart.od_id=g5_shop_order.od_id 
WHERE g5_shop_cart.od_id<>'' AND SUBSTR(g5_shop_order.od_time,1,10)<='2020-12-31'

DELETE A
FROM 회계분개표 AS A LEFT JOIN 회계제목관리 AS B ON A.연결ID=B.ID
WHERE A.구분='분개' AND A.연결ID<>0 AND B.날짜 IS NULL

참조 : extbrain.tistory.com/74

[MySQL] DELETE LEFT JOIN

 

 

http://www.mysqltutorial.org/mysql-delete-join/

MySQL DELETE JOIN: Deleting Data from Multiple Tables

MySQL DELETE JOIN with LEFT JOIN

We often use the LEFT JOIN clause in the SELECT statement to find rows in the left table that have or don’t have matching rows in the right table.

We can also use the LEFT JOIN clause in the DELETE statement to delete rows in a table (left table) that does not have matching rows in another table (right table).

The following syntax illustrates how to use DELETE statement with LEFT JOIN clause to delete rows from T1 table that does not have corresponding rows in the T2 table:

1 2 3 4 5 6

DELETE T1 FROM T1         LEFT JOIN     T2 ON T1.key = T2.key WHERE     T2.key IS NULL;

Note that we only put T1 table after the DELETE keyword, not both T1 and T2 tables like we did with the INNER JOIN clause.