How to create fast database queries

Archive for March 4th, 2009

Aggregate concatenation

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Aggregate concatenation functions help creating a concatenated list out of a recordset. Useful for reports, hierarchical trees, etc.

MySQL supplies GROUP_CONCAT for this purpose. SYS_CONNECT_BY PATH and FOR XML can be used in Oracle and MS SQL.

In PostgreSQL, we cannot use these tricks, but we can create our own aggregate function. And this function will also accept two more extremely useful parameters: DELIMITER and IS_DISTINCT.
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Written by Quassnoi

March 4th, 2009 at 9:00 pm

Posted in PostgreSQL