Make COUNT returns error if there is no result, show warnings if there are too many parameters #2139

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wxiaoguang · 2022-04-25T06:33:18Z

wxiaoguang commented

2022-04-25 06:33:18 +00:00

Background

Developers may make mistakes about COUNT, eg: SELECT COUNT(*) FROM table LIMIT 10, which produces unexpected result. A simple COUNT should already have one row result. If not, there must be something wrong.
Databases have limitations about the number of preparted statement parameters.

Solution

To handle all similar problems gracefully in future, some improvements from XORM side:

Make XORM's Count return an error if the result is 0 row.
Make XORM report warnings for SQLs with more than xxxx parameters (eg: 16384), then users/developers can know there is something needed to be refactored, they have enough time to optimize the query before the hard limit comes.

# Background 1. Developers may make mistakes about `COUNT`, eg: `SELECT COUNT(*) FROM table LIMIT 10`, which produces unexpected result. A simple `COUNT` should already have one row result. If not, there must be something wrong. 2. Databases have limitations about the number of preparted statement parameters. # Solution To handle all similar problems gracefully in future, some improvements from XORM side: 1. Make XORM's Count return an error if the result is 0 row. 2. Make XORM report warnings for SQLs with more than xxxx parameters (eg: 16384), then users/developers can know there is something needed to be refactored, they have enough time to optimize the query before the hard limit comes.

lunny added the

kind

enhancement

label 2022-04-25 07:06:50 +00:00

lunny added this to the 1.3.1 milestone 2022-04-25 07:07:02 +00:00

lunny modified the milestone from 1.3.1 to 1.3.2

2022-05-31 02:23:50 +00:00

lunny modified the milestone from 1.3.2 to 1.3.3

2022-09-03 07:12:16 +00:00

lunny referenced a pull request that will close this issue

2023-07-20 10:36:53 +00:00

Return error if count returned no row #2298