


Why Does My MySQL `NOT IN` Subquery with Multiple Columns Return 'Operand Should Contain 1 Column'?
Jan 12, 2025 am 09:48 AMMySQL NOT IN
"Operation should contain 1 column" error caused by multiple columns in subquery
It is common to encounter the "operand should contain 1 column" error when using the NOT IN
clause of a subquery that contains multiple columns. This error arises from the restriction that the NOT IN
clause expects the subquery to return only a single column.
In the query provided:
SELECT * from campaigns WHERE id not in ( SELECT e.id_campaign, d.name, d.frequency, d.country, d.referral, d.bid, d.status, COUNT(e.id) AS countcap FROM campaigns d LEFT JOIN served e ON d.id = e.id_campaign WHERE d.status = 'Active' GROUP BY e.id_campaign HAVING countcap < d.frequency )
The subquery returns eight columns (id_campaign, name, frequency, country, referral, bid, status, and countcap). However, the NOT IN
clause requires a single column for comparison.
Solution:
To fix this error, we need to modify the subquery so that it only returns the id_campaign
column, which is the column we want to check for non-membership in the main query:
SELECT * FROM campaigns WHERE id NOT IN ( SELECT id_campaign FROM ( SELECT e.id_campaign AS id_campaign, d.frequency, e.id FROM campaigns d LEFT JOIN served e ON d.id = e.id_campaign WHERE d.status = 'Active' GROUP BY e.id_campaign HAVING COUNT(e.id) < d.frequency ) AS subquery );
By limiting the subquery results to a single column id_campaign
, we eliminate the "operand should contain 1 column" error and ensure that the NOT IN
clause performs the comparison correctly. Note that we added an alias subquery
to organize the query more clearly. This modified query will only return rows in the campaigns
table where id
is not in the subquery results.
The above is the detailed content of Why Does My MySQL `NOT IN` Subquery with Multiple Columns Return 'Operand Should Contain 1 Column'?. For more information, please follow other related articles on the PHP Chinese website!

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