Results for “SQL”
Small, practical examples. Search by task or narrow things down below.
Find records without any related rows
Postgres: NOT EXISTS avoids the NULL pitfalls of NOT IN when the subquery column can be missing.
Postgres✓ Tested
Find rows in the first result but not the second
Postgres: EXCEPT calculates a distinct result-set difference.
Postgres✓ Tested
Find rows shared by two query results
Postgres: INTERSECT compares complete selected rows and removes duplicates.
Postgres✓ Tested
Find rows with a related record
Use EXISTS without duplicating the outer rows.
EXISTS✓ Tested
Find the final day of a month
Use EOMONTH without manually calculating month length.
EOMONTH✓ Tested
Find the first day of a month
Round a date to its calendar month boundary.
date✓ Tested
Find the second-highest distinct value
Postgres: Select the maximum below the overall maximum to skip ties at the top.
Postgres✓ Tested
Format a timestamp
Extract a year and month from ISO timestamp text.
strftime✓ Tested
Format a timestamp with to_char
Produce a fixed numeric date string.
to_char✓ Tested
Generate a bounded sequence recursively
Use a recursive CTE with a recursion limit.
recursive CTE✓ Tested
Generate a sequence of numbers
Create rows without a stored table.
generate_series✓ Tested
Generate every combination of two sets
Postgres: CROSS JOIN creates one result per possible pair, so the output size is the product of the input sizes.
Postgres✓ Tested