Question

In a previous question I asked how I could sum up a total based on some conditions: Count total on couple of conditions

Suppose I have a table like this:

id     col1     col2     col3
1      a        1        k1
2      a        2        k2
3      a        -3       k3
4      b        3        k4

Now, when I get id=1, I want to delete all the rows where col1=a.
When I get id=4, I want to delete all the rows where col1=b.

How would I do this in SQL?

I tried based upon previous answer:

DELETE FROM table WHERE (col1) IN (SELECT col1 FROM table WHERE id = '1')

But that gave me an error: #1093 - You can't specify target table 'table' for update in FROM clause

Answer 1

This has been many times on stackowerflow, you cannot UPDATE/DELETE table with data from nested select on the same table. There’re two ways to do this:

• Load all data before (for example via php, sql procedure)
• Create temporary table like the one you’re using, clone data and use temporary table to select items