Results for “Postgres”
Small, practical examples. Search by task or narrow things down below.
Sum a row and its immediate predecessor
Postgres: A ROWS frame counts physical ordered rows rather than all peers with the same sort value.
Postgres✓ Tested
Treat an empty trimmed value as missing
Postgres: NULLIF converts an empty string to NULL before a fallback is applied.
Postgres✓ Tested
Turn a condition into a result label
Postgres: Use CASE to describe stock availability for each row.
Postgres✓ Tested
Turn known group values into columns
Postgres: Conditional aggregation gives a portable pivot when the category set is known.
Postgres✓ Tested
Undo a multi-row transfer atomically
Postgres: The first transaction commits the fixtures. Rolling back the second transaction restores both sides of the attempted transfer.
Postgres✓ Tested
Undo only the work after a savepoint
Postgres: After committing the fixtures, roll back a trial change while keeping earlier work in the second transaction.
Postgres✓ Tested
Update one row using its primary key
Postgres: Use a precise WHERE condition to change only the intended row in a scratch table.
Postgres✓ Tested
Update rows selected by a related table
Postgres: Use EXISTS to limit updates based on an independent eligibility table.
Postgres✓ Tested
Update several classifications in one statement
Postgres: A CASE expression computes the new value for each row covered by the update predicate.
Postgres✓ Tested
Accept either of two conditions
SQL: Use OR to keep matching names or out-of-stock rows.
SQL✓ Tested
Add an interval to a date
Perform calendar arithmetic with an interval literal.
INTERVAL✓ Tested
Add an optional field to an existing table
SQL: A nullable column permits existing rows to remain valid while data is filled later.
SQL✓ Tested