The snippet library.
Small, practical examples. Search by task or narrow things down below.
Attach an overall count to every row
SQL: An uncorrelated scalar subquery supplies the same aggregate to each output row.
SQL✓ Tested
Build a query from several named stages
SQL: Separate row selection from aggregation using two common table expressions.
SQL✓ Tested
Compare a row with its own group average
SQL: A correlated aggregate computes a different comparison value for each group.
SQL✓ Tested
Find the second-highest distinct value
SQL: Select the maximum below the overall maximum to skip ties at the top.
SQL✓ Tested
Include every row tied for the highest score
SQL: Compare with MAX rather than limiting to an arbitrary number of rows.
SQL✓ Tested
Include missing values in a not-equal filter
SQL: Ordinary inequality does not include NULL; explicitly include it when that is the intended rule.
SQL✓ Tested
Read a page after a known unique key
SQL: A keyset predicate avoids scanning and discarding an increasing offset on a suitable index.
SQL✓ Tested
Report duplicate business values and their frequency
SQL: Group by a candidate business key and retain only groups with multiple rows.
SQL✓ Tested
Return all rows tied for the maximum in a group
SQL: An equality comparison with a grouped maximum retains ties rather than choosing one arbitrary row.
SQL✓ Tested
Sort preferred rows ahead of other rows
SQL: A CASE ordering key expresses business priority before a stable secondary sort.
SQL✓ Tested