The snippet library.
Small, practical examples. Search by task or narrow things down below.
Select the top row in each group with a tie-breaker
SQL: Filter an outer query on ROW_NUMBER because window functions are not evaluated in WHERE.
SQL✓ Tested
Select values in an inclusive range
SQL: BETWEEN includes both endpoints of the range.
SQL✓ Tested
Show a group total beside each detail row
SQL: A partitioned aggregate preserves detail rows instead of collapsing them with GROUP BY.
SQL✓ Tested
Sort preferred rows ahead of other rows
SQL: A CASE ordering key expresses business priority before a stable secondary sort.
SQL✓ Tested
Sort the highest quantities first
SQL: Specify descending order and a stable tie breaker.
SQL✓ Tested
Sum a row and its immediate predecessor
SQL: A ROWS frame counts physical ordered rows rather than all peers with the same sort value.
SQL✓ Tested
Sum values per category
Calculate a grouped total.
SUM✓ Tested
Test missing values with IS NULL
Find rows where an optional value is absent.
IS NULL✓ Tested
Treat an empty trimmed value as missing
SQL: NULLIF converts an empty string to NULL before a fallback is applied.
SQL✓ Tested
Turn a condition into a result label
SQL: Use CASE to describe stock availability for each row.
SQL✓ Tested
Turn known group values into columns
SQL: Conditional aggregation gives a portable pivot when the category set is known.
SQL✓ Tested
Undo a multi-row transfer atomically
SQL: The first transaction commits the fixtures. Rolling back the second transaction restores both sides of the attempted transfer.
SQL✓ Tested