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Support for common table expressions (aka WITH) via special LINQ operator #26486
Description
We could have a special queryable-returning function which we'd translate into a TableExpressionBase:
from foo in EF.With(ctx.Foos.Where(....))
from bar in EF.With(ctx.Bars.Where(....))
from baz in ctx.Bazes.Where(...)
...... becomes:
WITH foo AS (
SELECT * FROM Foos
WHERE ...
), bar AS (
SELECT * FROM Bars
WHERE ...
),
SELECT * FROM Bazes WHERE ...Do recursive CTEs as well.
Note: CTEs are also valid with WITH ... INSERT ... INTO, WITH ... DELETE, WITH ... UPDATE.
See also #29918 (embedded IQueryables to common table expressions)
Community implementations
Reacted by Albert Ragány-Németh, Massimiliano Donini, Steven Rasmussen, JohnEffo, sidneyxvr, levyhnunes, LucasLima, matt beary, Volodymyr Rets, Jan Jones and 127 more
Reacted by netotz, Denis Zimin, Viesturs Priedītis, Milo, Miguel Oliveira, Joona Luoma, Sujan Sapkota, Yimmy Quispe Yujra, David Thompson, Fabien Ménager and 10 more
Activity
[-]Support for common table expressions (aka WITH)[/-][+]Support for common table expressions (aka WITH) using LINQ[/+][-]Support for common table expressions (aka WITH) using LINQ[/-][+]Support for common table expressions (aka WITH) by translating LINQ query[/+]roji commentedon Dec 19, 2021
Note: all major databases support prefixing UPDATE/DELETE with CTEs (see #795 for bulk updates).
[-]Support for common table expressions (aka WITH) by translating LINQ query[/-][+]Support for common table expressions (aka WITH) via special LINQ operator[/+]roji commentedon Aug 27, 2023
Note: all databases - except SQL Server - support embedding CTEs within arbitrary subqueries inside the query;
This effectively makes CTEs an optional prefix of SelectExpression.
In addition, SQL Server (but not other databases) requires that column names be explicitly specified when they're not named within the subquery:
mojtabakaviani commentedon Nov 23, 2024
@ajcvickers and @roji
I hope CTEs and window functions #12747 will be added to 10.0 milestone for boost performance of advanced queries with grouping and aggregation.
Pepsi1x1 commentedon Dec 6, 2024
+1 this would be great to see and would benefit us across a number of projects