In this tutorial, you have learned how to use the PostgreSQL STRING_AGG() function to concatenate strings and place a separator between them. ![]() The following picture shows the partial output: SELECTĬountry Code language: JavaScript ( javascript ) The email in each list separated by a semi-colon. Those coercions have been removed because they frequently caused surprising behaviors. The following example uses the STRING_AGG() function to build an email list for each country. 'Note: Before PostgreSQL 8.3, these functions would silently accept values of several non-string data types as well, due to the presence of implicit coercions from those data types to text. Here is the partial output: B) Using STRING_AGG() function to generate a list of emails This example uses the STRING_AGG() function to return a list of actor’s names for each film from the film table: SELECTį.title Code language: SQL (Structured Query Language) ( sql ) A) Using STRING_AGG() function to generate a list of comma-separated values We will use the film, film_actor, and actor tables from the sample database for the demonstration. PostgreSQL STRING_AGG() function examples Like other aggregate functions such as AVG(), COUNT(), MAX(), MIN(), and SUM(), the STRING_AGG() function is often used with the GROUP BY clause. The return type of the STRING_AGG() function is the string while the return type of the ARRAY_AGG() function is the array. The STRING_AGG() is similar to the ARRAY_AGG() function except for the return type. It has the following form: ORDER BY expression1, Code language: SQL (Structured Query Language) ( sql ) The order_by_clause is an optional clause that specifies the order of concatenated results. separator is the separator for concatenated strings.PostgreSQL offers two ways to concatenate strings. ![]() If you use other types than character string type, you need to explicitly cast these values of that type to the character string type. / How to Concatenate Strings in PostgreSQL. expression is any valid expression that can resolve to a character string.The STRING_AGG() function accepts two arguments and an optional ORDER BY clause. The following shows the syntax of the STRING_AGG() function: STRING_AGG ( expression, separator ) Code language: CSS ( css ) The function does not add the separator at the end of the string. The PostgreSQL STRING_AGG() function is an aggregate function that concatenates a list of strings and places a separator between them. Introduction to PostgreSQL STRING_AGG() function Summary: in this tutorial, you will learn how to use the PostgreSQL STRING_AGG() function to concatenate strings and place a separator between them. In PostgreSQL, the CONCAT function is used to concatenate two or more strings into one.
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