Edgewall Software

Opened 7 years ago

Closed 7 years ago

Last modified 7 years ago

#12656 closed enhancement (worksforme)

Allow common table expression in reports' SQL queries

Reported by: thenor Owned by:
Priority: normal Milestone:
Component: report system Version:
Severity: trivial Keywords: postgresql
Cc: Branch:
Release Notes:
API Changes:
Internal Changes:


The trac reporting systems performs some rewriting of SQL queries in reports. The consequence is that the query must be a SELECT.

However, for instance th:SubticketsPlugin needs a way to perform recursive queries in order to report on ticket hierarchies - and that is not possible in a simple SELECT. This is currently solved by means of a manually installed stored procedure that in turn is called through a normal SELECT. It is described in more detail here: th:SubticketsPlugin/Reporting.

The technique used in the plugin is a Common Table Expression; it is described here: https://www.postgresql.org/docs/9.1/static/queries-with.html

I suspect that e.g. th:MasterTicketsPlugin and other plugins that deal with ticket relations could benefit from a similar improvement. Plus, use of WITH can simplify many "ordinary" queries.

If that turns out to be unrealistic, it would be helpful if there was a nice way to install stored procedures in a reasonably database-independent manner through plugins' initialisation code.

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Change History (5)

comment:1 by Jun Omae, 7 years ago

I tried the following query on Trac 1.0.13 and 1.2. It seems to be worked.

    VALUES (1)
    SELECT n+1 FROM t WHERE n < 100
SELECT sum(n) FROM t

Also, I think you could wrap with SELECT * FROM (WITH ...) if it doesn't work.

I'd like to close as wontfix.

comment:2 by Jun Omae, 7 years ago

Keywords: postgresql added

comment:3 by Jun Omae, 7 years ago

According to this entry, CTE query would be available since MySQL 8.0.

comment:4 by theodor.norup@…, 7 years ago

Resolution: wontfix
Status: newclosed

Sorry, I feel a bit stupid, works for me as well. Wonder, what I've been mixing up…

Maybe it is relevant to mention this possibility explicitly in the report documentation?

in reply to:  4 comment:5 by Ryan J Ollos, 7 years ago

Resolution: wontfixworksforme

Replying to theodor.norup@…:

Maybe it is relevant to mention this possibility explicitly in the report documentation?

Sure, feel free to edit TracReports. A statement after the last sentence in TracReports#CreatingCustomReports might be appropriate.

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