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Support for int IndexOf(string value, int startIndex)

See original GitHub issue

Currently

We Currently have an implementation of int IndexOf(string value) calling column.IndexOf("#") <= 1 that gets (roughly) translated into `

LOCATE('#', `j`.`column`) - 1) > 1

Implementing int IndexOf(string value, int startIndex) means we can use the form LOCATE('#',column,X)=0 for column.IndexOf("#", X) == -1. A way to currently achieve this implementation is to use Substring(1).IndexOf("#") == -1 which however results in a fairly interesting:

(LOCATE('#', SUBSTRING(`j`.`column`, 1 + 1, CHAR_LENGTH(`j`.`column`))) - 1) = -1

Issue Analytics

State:
Created a year ago
Comments:8 (3 by maintainers)

Top GitHub Comments

1reaction

LeaFrockcommented, May 16, 2022

Wiki updated as requested. Since you’re a collaborator, you should see an Edit button on the page to allow you to edit the markdown.

Thanks for your update. I’m just a normal contributor 😄 and the edit button is hidden to me.

1reaction

rojicommented, May 16, 2022

@mguinness @lauxjpn @LeaFrock it turns out this actually was implemented for SQL Server in https://github.com/dotnet/efcore/pull/26623, for 7.0.0-preview.1. There’s a specification test for it as well, but since it was using a top-most projection, the test can client-eval and always passes regardless of whether a provider implements translation support or not. I opened https://github.com/dotnet/efcore/pull/28031 to improve the tests.

Note that SQLite and PostgreSQL do not have a function which accepts a start position parameter.