Results for “Postgres”
Small, practical examples. Search by task or narrow things down below.
Match one value from a short list
SQL: Use IN for a set of allowed values.
SQL✓ Tested
Measure the length of ordinary text
SQL: Use the engine’s text-length function; this ASCII example has no trailing spaces.
SQL✓ Tested
Name an intermediate query with a CTE
Make a filtered result reusable within one statement.
CTE✓ Tested
Normalize ASCII text to lowercase
SQL: LOWER is useful for display normalization; indexed case-insensitive search depends on the database collation and schema.
SQL✓ Tested
Normalize ASCII text to uppercase
SQL: UPPER changes character case under the database’s text rules.
SQL✓ Tested
Number rows within each group
Assign ordered row numbers with a window function.
row_number✓ Tested
Pair employees with their managers
SQL: Alias a table twice to represent two different roles in one relationship.
SQL✓ Tested
Place missing values after known values portably
SQL: A CASE sort key controls NULL placement without relying on engine-specific defaults.
SQL✓ Tested
Rank tied scores with competition gaps
SQL: RANK leaves a gap after tied rows, unlike DENSE_RANK.
SQL✓ Tested
Rank tied scores without gaps
SQL: DENSE_RANK assigns equal ranks to ties and increments by one for the next distinct score.
SQL✓ Tested
Read a JSONB field as text
Extract a nested value from a JSON document.
jsonb✓ Tested
Read a page after a known unique key
SQL: A keyset predicate avoids scanning and discarding an increasing offset on a suitable index.
SQL✓ Tested