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Clarify that unaggregated variables in SELECT raise an error #327

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Clarify that unaggregated variables in SELECT raise an error #327

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c2c6862
Clarify a note on unagreggated variables
Tpt Dec 12, 2025
efb2b9c
Update spec/index.html
Tpt Dec 12, 2025
3f3e302
Makes the translation algorithm raise an error on unnagregatted varia…
Tpt Dec 13, 2025
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16 changes: 9 additions & 7 deletions spec/index.html
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Original file line number Diff line number Diff line change
Expand Up @@ -2925,12 +2925,14 @@ <h3>Aggregate Projection Restrictions</h3>
?x :q ?z .
} GROUP BY ?x (STR(?z))
</pre>
<p>Note that it would not be legal to project <code>STR(?z)</code> as this is not a simple
variable expression. However, with <code>GROUP BY (STR(?z) AS ?strZ)</code> it would be
possible to project <code>?strZ</code>.</p>
<p>Other expressions, not using <code>GROUP BY</code> variables, or aggregates may have
non-deterministic values projected from their groups using the <code>SAMPLE</code>
aggregate.</p>
<div class="note">
<p>Note that it would not be legal to project <code>STR(?z)</code> as this is not a simple
variable expression. However, with <code>GROUP BY (STR(?z) AS ?strZ)</code> it would be
possible to project <code>?strZ</code>.</p>
<p>For other expressions (not using <code>GROUP BY</code> variables or aggregates),
non-deterministic values may be requested from their groups by using the <code>SAMPLE</code>
aggregate function explicitly.</p>
</div>
</section>
<section id="aggregateExample2">
<h3>Aggregate Example (with errors)</h3>
Expand Down Expand Up @@ -9538,7 +9540,7 @@ <h5>Grouping and Aggregation</h5>

For each (<var>X</var> AS <var>Var</var>) in SELECT, each HAVING(<var>X</var>), and each ORDER BY <var>X</var> in <var>Q</var>
For each unaggregated variable <var>V</var> in <var>X</var>
Replace <var>V</var> with SAMPLE(<var>V</var>)
Raise an error
End
For each aggregate <var>R</var>(<var>args</var> ; <var>scalarvals</var>) now in <var>X</var>
# note: <var>scalarvals</var> may be omitted; if so, it is equivalent to the empty function
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