Results for “Postgres”
Small, practical examples. Search by task or narrow things down below.
Combine results while retaining duplicates
Postgres: UNION ALL does not spend work removing equal rows.
Postgres✓ Tested
Combine text values with a separator
Postgres: Use the concatenation operator supported by the selected SQL dialect.
Postgres✓ Tested
Commit multiple related changes together
Postgres: The first transaction prepares the fixtures. The second commits both updates as one unit.
Postgres✓ Tested
Compare a row with its own group average
Postgres: A correlated aggregate computes a different comparison value for each group.
Postgres✓ Tested
Compute an integer weighted average
Postgres: Multiply before summing and guard a zero total weight with NULLIF.
Postgres✓ Tested
Copy selected rows into another table
Postgres: INSERT SELECT performs a set-based copy with an explicit destination column list.
Postgres✓ Tested
Count distinct values within a result
Postgres: COUNT DISTINCT counts distinct non-null values.
Postgres✓ Tested
Count rows satisfying separate conditions
Postgres: SUM over CASE expressions calculates several conditional counts in one scan.
Postgres✓ Tested
Count the rows in a table
Postgres: COUNT(*) includes every row, including rows with NULL columns.
Postgres✓ Tested
Create a table and insert its first row
Postgres: Define column types and a primary key, then insert one row using an explicit column list.
Postgres✓ Tested
Create an index for an equality filter
Postgres: A nonunique index can support lookups on a frequently filtered column.
Postgres✓ Tested
Create an index matching filter and ordering columns
Postgres: Place the equality-filter column before the ordering column in this composite index.
Postgres✓ Tested