Common Table Expressions (CTEs) are a very useful tool and
frankly a big improvement on sub-queries. But there are
differences in how they are implemented in MySQL and
MariaDB. That is not too surprising since the code
fork many years ago. Different engineers implementing the same
idea will have different approaches (and sometimes results). But
differences in implementation are often important and, in this
case, shockingly different.
Jesper Wisborg Krogh at Oracle OpenWorld and CodeOne gave a
series of presentations and hands on labs that were excellent. He
is an amazing Support Engineer and a great presenter of material
at conferences. In the lab for Common Table Expressions he
did point out to me an interesting problem in MariaDB's
implementation of CTEs.
The Problem In a Nutshell
On the PostgreSQL Wiki, there is a
an SQL query (requires PostgreSQL 8.4 or MySQL 8.0) that …
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Nov
06
2018
Showing entries 1 to 1