HAVING & aggregate conditions

Filter a group, not a row

Lesson 8 of 20 · 9 min · Module 3: See patterns in data

A report can first combine individual records into groups, then keep only groups meeting an aggregate condition.

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By the end, you’ll be able to…

Distinguish row and group conditions
Use COUNT and SUM in one report
Read the stages of an aggregate query

The idea

WHERE filters individual rows before grouping. HAVING filters groups after aggregates such as COUNT or SUM have been calculated.

SELECT language, COUNT(*) AS learners
FROM learners
GROUP BY language
HAVING COUNT(*) > 1;

01Follow the logical stages

Start from learners, group the rows by language, count each group, and add its XP. HAVING decides which groups remain. ORDER BY then arranges the result.

02Explain the example data

Python has Sam and Mia, totaling 430 XP. JavaScript has Alex and Jordan, totaling 210. SQL has only Lee, so its group does not satisfy the condition.

Your turn

For languages with more than one learner, return language and SUM(xp). Sort the totals from highest to lowest.

What the checks look for

Returns Python (430) and JavaScript (210)

Try it in the editor →

Take this with you

Use HAVING when the condition depends on the whole group.