Results for “missing data”
Small, practical examples. Search by task or narrow things down below.
Keep parent rows while filtering joined children
Postgres: Put a child filter in ON when unmatched parents must remain in the result.
Postgres✓ Tested
Keep parent rows while filtering joined children
SQLite: Put a child filter in ON when unmatched parents must remain in the result.
SQLite✓ Tested
List unordered pairs without duplicate reversals
SQL: Join using an increasing key comparison to omit self-pairs and reversed duplicates.
SQL✓ Tested
List unordered pairs without duplicate reversals
SQL Server: Join using an increasing key comparison to omit self-pairs and reversed duplicates.
SQL Server✓ Tested
List unordered pairs without duplicate reversals
Postgres: Join using an increasing key comparison to omit self-pairs and reversed duplicates.
Postgres✓ Tested
List unordered pairs without duplicate reversals
SQLite: Join using an increasing key comparison to omit self-pairs and reversed duplicates.
SQLite✓ Tested
Pair employees with their managers
SQL: Alias a table twice to represent two different roles in one relationship.
SQL✓ Tested
Pair employees with their managers
SQL Server: Alias a table twice to represent two different roles in one relationship.
SQL Server✓ Tested
Pair employees with their managers
Postgres: Alias a table twice to represent two different roles in one relationship.
Postgres✓ Tested
Pair employees with their managers
SQLite: Alias a table twice to represent two different roles in one relationship.
SQLite✓ Tested
Find missing values with IS NULL
SQL: Use IS NULL rather than equality to test for missing data.
SQL✓ Tested
Find missing values with IS NULL
SQL Server: Use IS NULL rather than equality to test for missing data.
SQL Server✓ Tested