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You're reading from  Mastering PostgreSQL 15 - Fifth Edition

Product typeBook
Published inJan 2023
PublisherPackt
ISBN-139781803248349
Edition5th Edition
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Author (1)
Hans-Jürgen Schönig
Hans-Jürgen Schönig
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Hans-Jürgen Schönig

Hans-Jürgen Schönig has 20 years' experience with PostgreSQL. He is the CEO of a PostgreSQL consulting and support company called CYBERTEC PostgreSQL International GmbH. It has successfully served countless customers around the globe. Before founding CYBERTEC PostgreSQL International GmbH in 2000, he worked as a database developer at a private research company that focused on the Austrian labor market, where he primarily worked on data mining and forecast models. He has also written several books about PostgreSQL.
Read more about Hans-Jürgen Schönig

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Migrating SQL statements to PostgreSQL

When moving from a database to PostgreSQL, it makes sense to take a look and figure out which database engine provides which kind of functionality. Moving the data and the structure itself is usually fairly easy. However, rewriting SQL might not be. Therefore, I decided to include a section that explicitly focuses on various advanced features of SQL and their availability in today’s database engines.

Using LATERAL joins

In SQL, a LATERAL join can basically be seen as some sort of loop. This allows us to parameterize a join and execute everything inside the LATERAL clause more than once. Here is a simple example of this:

test=# SELECT *
   FROM generate_series(1, 4) AS x,
        LATERAL (SELECT array_agg(y)
                  FROM generate_series(1, x) AS y
     ...
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Mastering PostgreSQL 15 - Fifth Edition
Published in: Jan 2023Publisher: PacktISBN-13: 9781803248349

Author (1)

author image
Hans-Jürgen Schönig

Hans-Jürgen Schönig has 20 years' experience with PostgreSQL. He is the CEO of a PostgreSQL consulting and support company called CYBERTEC PostgreSQL International GmbH. It has successfully served countless customers around the globe. Before founding CYBERTEC PostgreSQL International GmbH in 2000, he worked as a database developer at a private research company that focused on the Austrian labor market, where he primarily worked on data mining and forecast models. He has also written several books about PostgreSQL.
Read more about Hans-Jürgen Schönig