Results for “Postgres”
Small, practical examples. Search by task or narrow things down below.
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 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
Join a parent to pre-aggregated totals
SQL: Aggregate the child rows first to produce at most one joined row per parent.
SQL✓ Tested
Join related rows from two tables
SQL: Match a category key to its display label with an explicit join condition.
SQL✓ Tested
Join text rows in a chosen order
Combine values using string_agg.
string_agg✓ Tested