On Tue, 2023-04-25 at 16:43 +0100, e-letter wrote:
> table1
> column1,column2
> value1,value2
>
> table2
> column2,column3
> value2, value3
>
> table3
> column1,column2,column3
> value1,value2,value3
>
> When value3 is first entered into table2, what are the correct
> commands for value2 (in table2) and value1 (in table1) to be selected
> for insertion into table 3?
>
> INSERT INTO table3 SELECT ... WHERE value3='...';
>
> The conceptual difficulty is how to use nested query correctly, or is
> there a better method? Thank you.
The question is a bit unclear, but perhaps you mean
INSERT INTO table3 (column1, column2, column3)
SELECT table1.column1,
table1.column2,
table2.column3
FROM table1
JOIN table2 USING (column2)
WHERE table2.column3 = 'value3';
Yours,
Laurenz Albe
