Results for “os”
Small, practical examples. Search by task or narrow things down below.
Toggle a native popover from a button
HTML: The popovertarget relationship handles show and hide behavior without a click handler.
HTML✓ 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
Use a build argument while creating an image
Docker / Compose: ARG supplies a build-time value that is not automatically a runtime environment variable.
Docker / Compose✓ Tested
Use a function’s exit status as a boolean result
Bash Scripts: Return zero for success and test the function directly in a conditional.
Bash Scripts✓ Tested
Use a recursive function for a bounded calculation
Bash Scripts: A recursive factorial demonstrates local variables and a clear base case.
Bash Scripts✓ Tested