query very very slow
Ilona Kleiman
Peter Horsbøll Møller
Hi Ilona
It’s a side effect of some of the many improvements we made to the SQL language in v2019, especially the Cross Join support that was added.
We did make some further improvements in v2019.3 so make sure you are using the latest version and build: v2019.3 Build 45.
You can download it from here: https://support.precisely.com/product-downloads/item/mapinfo-pro-v2019-3-evaluation-version/
There is another workaround that can be applied that also requires v2019.3.
Run this statement:
Set SQL Version 1900
then run this query
From the support documentation:
Purpose
To control the behavior of the join condition evaluation order and support for cross-joins in a session.
Syntax
Set SQL Version version_num
version_num is a value of either 1900 or 1700.
A version number higher than 1900 will default to 1900, and a version number lower than 1900 will set the SQL version to 1700.
A version less than 1900 will set MapInfo Pro to use the old SQL behavior - join conditions are evaluated from left to right, and support for cross-joins is disabled. To allow cross-joins with SQL version 1700, use the Cross Join keyword explicitly in the SQL Select statement. This would also change the order of evaluation of join conditions from right to left for the particular SQL Select statement.
A version number greater than or equal to 1900 will set MapInfo Pro to use the new SQL behavior - join conditions are evaluated from right to left, and support for cross joins is enabled. In this case, you can perform cross-joins with or without using the Cross Join keyword in the SQL Select statement.
Note: The default SQL version is set to 1700, cross-join support is not available by default, and join conditions are evaluated from left to right.
Description
Controls the behaviour of the join condition evaluation order and support for cross-joins in a session.
Let us know if this helps
From: mapi...@googlegroups.com <mapi...@googlegroups.com>
On Behalf Of Ilona Kleiman
Sent: 6. marts 2022 10:51
To: MapInfo-L <mapi...@googlegroups.com>
Subject: [MI-L] query very very slow
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