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Why Does My SQL Count Return All Rows Instead of Individual Rows?

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2025-01-18 05:51:07279browse

Why Does My SQL Count Return All Rows Instead of Individual Rows?

Troubleshooting SQL COUNT: Getting Individual Row Counts

Your SQL query likely produces an incorrect total row count because it's missing a crucial GROUP BY clause. The example shows a count of 2 for the top row, indicating a problem with aggregation.

The provided complex query's core issue lies within the subquery calculating the Aura count:

<code class="language-sql">LEFT JOIN
(
    select `ID` as `AuraID`, `Status` as `AuraStatus`, count(*) as `Aura`
    from messages_aura
) aura ON (var.Poster = aura.AuraID AND var.ID = aura.AuraStatus)</code>

This subquery, without a GROUP BY clause, sums all rows in messages_aura, irrespective of AuraID or AuraStatus. Hence, it always returns the table's total row count (2 in your case).

The solution is to add a GROUP BY clause to correctly group and count:

<code class="language-sql">LEFT JOIN
(
    select `ID` as `AuraID`, `Status` as `AuraStatus`, count(*) as `Aura`
    from messages_aura
    GROUP BY `AuraID`, `AuraStatus`
) aura ON (var.Poster = aura.AuraID AND var.ID = aura.AuraStatus)</code>

This revised subquery groups messages_aura rows by AuraID and AuraStatus, accurately counting Aura for each group. This correction will yield the expected results—1 for the bottom row and 2 for the top row.

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