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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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