Question

I mean I’ve got one table

table1
idbook idauthor  title     magazine
 1       NULL   title_1   magazine_1
 2        2     title_2   magazine_2

and another

table2
idauthor   name     surname
   1      name_1   surname_1
   2      name_2   surname_2

And I want to write a query which update table1 and set value ‘idauthor’ for title_1 the same as the ‘idauthor’ in table2 with name_1.

How it will be look like?Or it is not possible?

How

Answer 1

Actually, the common column is idauthor, it could be thought of as a foreign key. But since there is no way to match table1’s row with table2, you would have to do kind of a dirty update statement, that will ONLY work for the example given above, and not for other scenarios.

UPDATE table1 SET idauthor = (SELECT idauthor FROM table2 WHERE name LIKE "name_1" AND surname LIKE "surname_1") WHERE idauthor ISNULL;

This query would update ALL of table1’s rows that have a NULL value in the idauthor column, and set it to the one you’re searching with name_1 and surname_1.