Results for “Relationships & missing data”
Small, practical examples. Search by task or narrow things down below.
Find missing values with IS NULL
Postgres: Use IS NULL rather than equality to test for missing data.
Postgres✓ Tested
Find missing values with IS NULL
SQLite: Use IS NULL rather than equality to test for missing data.
SQLite✓ 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
Include missing values in a not-equal filter
SQL Server: Ordinary inequality does not include NULL; explicitly include it when that is the intended rule.
SQL Server✓ Tested
Include missing values in a not-equal filter
Postgres: Ordinary inequality does not include NULL; explicitly include it when that is the intended rule.
Postgres✓ Tested
Include missing values in a not-equal filter
SQLite: Ordinary inequality does not include NULL; explicitly include it when that is the intended rule.
SQLite✓ Tested
Place missing values after known values portably
SQL: A CASE sort key controls NULL placement without relying on engine-specific defaults.
SQL✓ Tested
Place missing values after known values portably
SQL Server: A CASE sort key controls NULL placement without relying on engine-specific defaults.
SQL Server✓ Tested
Place missing values after known values portably
Postgres: A CASE sort key controls NULL placement without relying on engine-specific defaults.
Postgres✓ Tested
Place missing values after known values portably
SQLite: A CASE sort key controls NULL placement without relying on engine-specific defaults.
SQLite✓ Tested
Treat an empty trimmed value as missing
SQL: NULLIF converts an empty string to NULL before a fallback is applied.
SQL✓ Tested
Treat an empty trimmed value as missing
SQL Server: NULLIF converts an empty string to NULL before a fallback is applied.
SQL Server✓ Tested