How to use a field in one table to update a field in another table in MySQL

1. Modify 1 column

update student s, city c
set s.city_name = c.name
where s.city_code = c.code;

2. Modify multiple columns

update a, b
set a.title=b.title, a.name=b.name
where a.id=b.id

• Subqueries

update student s set city_name = (select name from city where code = s.city_code);

Oracle query reports this error: single-row subquery returns more than one row How to solve it?

The database has multiple duplicate data according to your query conditions.

For example:

UPDATE "SYS_ROLE" A
SET A ."DEPT_ID" = (
  SELECT
    c."id"
  FROM
    "his_department_info" c
  WHERE
    c."dept_name" = A ."ROLE_NAME"

If the above SQL statement reports the error "single-row subquery returns more than one row", it means that the data of the two fields "dept_name" in table C and "ROLE_NAME" in table A are repeated.

Summarize

The above is what I introduced to you on how to use the fields in one table in MySQL to update the fields in another table. I hope it will be helpful to you. If you have any questions, please leave me a message and I will reply to you in time. I would also like to thank everyone for their support of the 123WORDPRESS.COM website!