DB-Manager: strip comments from SQL

[elpaso]

Fixes #21271

[Gustry]

I think this function is used to store queries in preset or in file. They are many usages. So we will loose comments in saved file.

[elpaso]

@Gustry ok, I'll move it down into the executor

[elpaso]

@Gustry, looking better I thing you are wrong, the original behavior was altering the query by replacing newlines with spaces, and that was the source of the issue: https://github.com/qgis/QGIS/pull/9180/files#diff-9020444f364248acb9ad107f6fb38ba0L598

[Gustry]

getSqlQuery is used when we store the query as file:

QGIS/python/plugins/db_manager/dlg_sql_window.py

Line 234 in 6972372

query = self._getSqlQuery()

so it means that the content of the file is not the same? (especially with this PR)

Sorry if I didn't understand. I will look later.

[elpaso]

@Gustry can I merge?

[Gustry]

As I said, the _getSqlQuery is called also when you save the query as a file or as a preset, so your PR removes comments from saved query.

In DB Manager:

-- this is a comment
SELECT * FROM foo;

Save this query as a preset or as a file, it becomes:

SELECT * FROM foo;

IMHO, we need another function like getExecutableSqlQuery which call first getSqlQuery and then clean the query (remove comments, replace \n, strip).

BTW, I noticed another one regression from QGIS 2, comments on the same line are not working.

SELECT *  --all fields
FROM foo;

is not working in QGIS 3.4 while it's working fine in QGIS 2.18 and PgAdmin3 and 4.

[elpaso]

Superceeded by: #9183