Results for “Collections & data structures”
Small, practical examples. Search by task or narrow things down below.
Find parents with at least two child rows
SQLite: Use a correlated count when testing a per-parent threshold.
SQLite✓ Tested
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
Find shared members of two sets
JavaScript: Filter one set through the other set’s membership test.
JavaScript✓ Tested
Find shared members of two sets
TypeScript: Filter one set through the other set’s membership test.
TypeScript✓ Tested
Format an integer as padded hexadecimal
Format an integer as padded hexadecimal in a complete Rust program using the standard library.
Rust✓ 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