I could find a lot of similar questions but no real solution for my problem.
My SQL query:
UPDATE ADRESSEN
SET EMAIL = 0
WHERE ID = (SELECT ID, COUNT(ID) AS COUNTER
FROM EIGENSCHAFTEN WHERE Kategorie = "BOUNCE"
GROUP BY ID
HAVING COUNTER = 1)
The error code I receive is
#1241 - Operand should contain 1 column(s)
If I just use the query in the parentheses it works and the result is
ID | COUNTER
0002159 | 1
Where is my error? Thanks a lot for your help.