What is the purpose of group_concat in pgsql?

In PostgreSQL, there is no built-in group_concat function, but you can achieve similar functionality using the string_agg function. This function can concatenate the values of a specified column into a string, and you can also specify a delimiter for the concatenation.

For example, suppose there is a table called t with a column named name, we can use the following query to achieve a similar functionality to group_concat:

SELECT id, string_agg(name, ',') AS names
FROM t
GROUP BY id;

This will connect the names corresponding to each ID with a comma as a separator.