Language reference
CONCAT_WS (join with a separator, skipping NULLs)
Syntax
CONCAT_WS(<separator>, <value>, ...)
π CONCAT_WS(', ', city, region) → place (Customers)Description
CONCAT_WS joins values with a separator between each pair: CONCAT_WS('-', 'a', 'b') is 'a-b'. A missing value is left out together with its separator, so optional parts do not leave doubled separators behind.
Technical Description
CONCAT_WS(separator: STRING, value, …) → STRING. One or more values of any type, each written as it displays; NULL values are skipped. A NULL separator gives NULL. PURE, DETERMINISTIC.
Examples
An address from optional parts:
π CONCAT_WS(', ', city, region) → place (Customers)PROJECT CONCAT_WS(', ', city, region) -> place (Customers)Pushdown
Runs in the engine: a backend writes numbers and dates as text its own way.