Results for “Relationships & missing data”
Small, practical examples. Search by task or narrow things down below.
Find records without any related rows
SQL: NOT EXISTS avoids the NULL pitfalls of NOT IN when the subquery column can be missing.
SQL✓ Tested
Find records without any related rows
SQL Server: NOT EXISTS avoids the NULL pitfalls of NOT IN when the subquery column can be missing.
SQL Server✓ Tested
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 records without any related rows
SQLite: NOT EXISTS avoids the NULL pitfalls of NOT IN when the subquery column can be missing.
SQLite✓ Tested
Generate every combination of two sets
SQL: CROSS JOIN creates one result per possible pair, so the output size is the product of the input sizes.
SQL✓ Tested
Generate every combination of two sets
SQL Server: CROSS JOIN creates one result per possible pair, so the output size is the product of the input sizes.
SQL Server✓ 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
Generate every combination of two sets
SQLite: CROSS JOIN creates one result per possible pair, so the output size is the product of the input sizes.
SQLite✓ Tested
Join a parent to pre-aggregated totals
SQL: Aggregate the child rows first to produce at most one joined row per parent.
SQL✓ Tested
Join a parent to pre-aggregated totals
SQL Server: Aggregate the child rows first to produce at most one joined row per parent.
SQL Server✓ Tested
Join a parent to pre-aggregated totals
Postgres: Aggregate the child rows first to produce at most one joined row per parent.
Postgres✓ Tested
Join a parent to pre-aggregated totals
SQLite: Aggregate the child rows first to produce at most one joined row per parent.
SQLite✓ Tested