Results for “post”
Small, practical examples. Search by task or narrow things down below.
Get the latest row in each group
Select one ordered row per key with DISTINCT ON.
DISTINCT ON✓ Tested
Give a result column a readable name
SQL: Use AS to label a computed result column.
SQL✓ Tested
Group by more than one field
SQL: Each distinct combination of grouping fields produces its own row.
SQL✓ Tested
Include every row tied for the highest score
SQL: Compare with MAX rather than limiting to an arbitrary number of rows.
SQL✓ 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 zero counts for missing relationships
SQL: Count the non-null child key after a left join so a missing relationship produces zero.
SQL✓ Tested
Increment a counter without an unexpected errexit
Bash Scripts: An assignment avoids the zero-result exit status of a standalone arithmetic post-increment.
Bash Scripts✓ Tested
Increment a stored value in the database
SQL: An in-database arithmetic update avoids a separate application read-modify-write step.
SQL✓ Tested
Insert a row with named columns
Add a record without relying on implicit column order.
INSERT✓ Tested
Insert only keys absent from a destination
SQL: NOT EXISTS supports a set-based missing-row insert in a single-writer example.
SQL✓ Tested
Insert or update on a key conflict
Use a unique key to update an existing row.
ON CONFLICT✓ Tested
Inspect deleted rows
Return values from the rows a DELETE removes.
DELETE✓ Tested