The snippet library.
Small, practical examples. Search by task or narrow things down below.
Remove surrounding spaces from text
Postgres: TRIM removes leading and trailing space characters by default.
Postgres✓ Tested
Repeat the first ordered value beside each row
Postgres: FIRST_VALUE reads the first value in the current window frame.
Postgres✓ Tested
Replace a literal substring
Postgres: REPLACE performs a literal replacement rather than a regular-expression substitution.
Postgres✓ Tested
Replace a nested JSONB value
Change one path with jsonb_set.
jsonb_set✓ Tested
Replace all matching text
Normalize repeated whitespace with a regular expression.
regexp_replace✓ Tested
Report duplicate business values and their frequency
Postgres: Group by a candidate business key and retain only groups with multiple rows.
Postgres✓ Tested
Require a value with NOT NULL
Postgres: Declare required fields at the database boundary, not only in application validation.
Postgres✓ Tested
Require two filtering conditions
Postgres: Combine category and quantity conditions with AND.
Postgres✓ Tested
Return all rows tied for the maximum in a group
Postgres: An equality comparison with a grouped maximum retains ties rather than choosing one arbitrary row.
Postgres✓ Tested
Return an inserted row
Read generated data directly from INSERT.
RETURNING✓ Tested
Return zero for a sum over no rows
Postgres: SUM produces NULL for an empty input; COALESCE supplies the desired reporting default.
Postgres✓ Tested
Round a timestamp down to its month
Group dates by a calendar boundary.
date_trunc✓ Tested