STRING_AGG

Aggregate function.

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

Analyze Syntax


func.string_agg(<expr> [, delimiter])

Analyze Examples


func.string_agg(table.language_name).alias('concatenated_languages')

|          concatenated_languages         |
|-----------------------------------------|
| Python, JavaScript, Java, C#, Ruby      |

SQL Syntax


STRING_AGG(<expr>)
STRING_AGG(<expr> [, delimiter])

Note:

If <expr> is not a String expression, should use ::VARCHAR to convert.

For example:


SELECT string_agg(number::VARCHAR, '|') AS s FROM numbers(5);
+-----------+
| s         |
+-----------+
| 0|1|2|3|4 |
+-----------+

Arguments

Arguments	Description
`<expr>`	Any string expression (if not a string, use `::VARCHAR` to convert)
`delimiter`	Optional constant String, if not specified, use empty String

Return Type

the String type

SQL Examples

Create a Table and Insert Sample Data


CREATE TABLE programming_languages (
  id INT,
  language_name VARCHAR
);

INSERT INTO programming_languages (id, language_name)
VALUES (1, 'Python'),
       (2, 'JavaScript'),
       (3, 'Java'),
       (4, 'C#'),
       (5, 'Ruby');

Query Demo: Concatenate Programming Language Names with a Delimiter


SELECT STRING_AGG(language_name, ', ') AS concatenated_languages
FROM programming_languages;

Result


|          concatenated_languages         |
|------------------------------------------|
| Python, JavaScript, Java, C#, Ruby      |