使用JOIN将Identical Id列插入第二张表插入第一张表

Question

I have a Database (MySQL) that contains two tables with identical primary keys, I have already inserted data into the first table but I want to insert data into the second table at a later time.

The logic I've got is:

[INSERT into Table2 (col1, col2, col3) Values (X1,X2,X3)  WHERE Table1.id equals Table2.id] 

I can't seem to find anything that works like this for an Insert Statement in use with PHP.

Any help appreciated!

Answer 1

It sounds like you really want to update the second table, not insert into it. INSERT is for creating new rows, UPDATE is for modifying existing rows.

You do this by using a JOIN in an UPDATE statement.

UPDATE Table2 AS t2
JOIN Table1 AS t1 ON t1.id = t2.id
SET t2.col1 = t1.x1, t2.col2 = t1.x2, t2.col3 = t1.x3