MySQL's TRIM statement in sqlalchemy

[Robert Buchholz]

Hello,

I am trying to write the following query in MySQL (in essence):
SELECT TRIM(TRAILING "-2" FROM c.slug)
FROM categories c;

In reality, the column this is run on is an anonymous aliased table in a
JOIN expression*. Is it possible to generate the TRIM(TRAILING X FROM Y)
with an SQLa function?


Cheers,

Robert



* The whole thing looks like this:
SELECT *
FROM categories c
JOIN categories c2
ON c.slug =
TRIM(TRAILING "-2" FROM c2.slug)
WHERE c2.slug LIKE "%-2";

[Michael Bayer]

Robert Buchholz <robert....@goodpoint.de> wrote:

> Hello,
>
> I am trying to write the following query in MySQL (in essence):
> SELECT TRIM(TRAILING "-2" FROM c.slug)
> FROM categories c;
>
> In reality, the column this is run on is an anonymous aliased table in a
> JOIN expression*. Is it possible to generate the TRIM(TRAILING X FROM Y)
> with an SQLa function?

this is a custom SQL format so you’d want to use @compiles. you can probably subclass ColumnElement. FunctionElement might work also, scan through http://docs.sqlalchemy.org/en/rel_0_9/core/compiler.html# for details.

>
>
> Cheers,
>
> Robert
>
>
>
> * The whole thing looks like this:
> SELECT *
> FROM categories c
> JOIN categories c2
> ON c.slug =
> TRIM(TRAILING "-2" FROM c2.slug)
> WHERE c2.slug LIKE "%-2";
>
>

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