STRING_AGG

Aggregate function.

The STRING_AGG() function converts all the non-NULL values of a column to String, separated by the delimiter.

Syntax

STRING_AGG(expression)
STRING_AGG(expression, delimiter)

Arguments

Arguments	Description
expression	Any String expression
delimiter	Optional constant String, if not specified, use empty String

Return Type

the String type

Examples

CREATE TABLE aggr(a string null);

INSERT INTO aggr VALUES
    ('abc'),
    ('def'),
    (null),
    ('xyz');

SELECT string_agg(a) FROM aggr;
+---------------+
| string_agg(a) |
+---------------+
| abcdefxyz     |
+---------------+

SELECT string_agg(a, '|') FROM aggr;
+--------------------+
| string_agg(a, '|') |
+--------------------+
| abc|def|xyz        |
+--------------------+