fix: ExecuteDeleteAsync with navigation property generates invalid SQL (MySQL Error 1093)

[Novoposarantus]

Problem

ExecuteDeleteAsync with a Where clause that traverses a navigation property (produces a LEFT JOIN) generates a DELETE ... WHERE id IN (SELECT id FROM same_table ...) subquery. MySQL 8.0 rejects this with Error 1093 — You can't specify target table for update in FROM clause.

Broken SQL (10.0.x)

DELETE FROM `Posts` AS `p`
WHERE `p`.`Id` IN (
    SELECT `p0`.`Id`
    FROM `Posts` AS `p0`
    LEFT JOIN `Blogs` AS `b` ON `p0`.`BlogId` = `b`.`Id`
    WHERE `b`.`Title` LIKE 'Arthur%'
)

Correct SQL (after fix)

DELETE `p`
FROM `Posts` AS `p`
LEFT JOIN `Blogs` AS `b` ON `p`.`BlogId` = `b`.`Id`
WHERE `b`.`Title` LIKE 'Arthur%'

Reproduction

// Any navigation-property predicate on ExecuteDeleteAsync triggers the bug:
await context.Posts
    .Where(p => p.Blog.Title.StartsWith("Arthur"))
    .ExecuteDeleteAsync();

Root Cause

MySqlQueryableMethodTranslatingExpressionVisitor.IsValidSelectExpressionForExecuteDelete only accepted InnerJoinExpression as extra tables. Navigation-property predicates produce LeftJoinExpression, so the method returned false, causing EF Core's base class to fall back to the subquery form.

The VisitDelete override in MySqlQuerySqlGenerator already handles LEFT JOINs correctly — it just never got reached.

Fix

One-line change in MySqlQueryableMethodTranslatingExpressionVisitor.cs:

- && selectExpression.Tables.Skip(1).All(t => t is InnerJoinExpression);
+ && selectExpression.Tables.Skip(1).All(t => t is InnerJoinExpression or LeftJoinExpression);

Test Updates

Tests previously expecting MySqlException (Error 1093) now assert the correct LEFT JOIN SQL:

• NonSharedModelBulkUpdatesMySqlTest.Delete_predicate_based_on_optional_navigation
• NorthwindBulkUpdatesMySqlTest.Delete_Where_using_navigation_2
• NorthwindBulkUpdatesMySqlTest.Delete_Where_optional_navigation_predicate
• NorthwindBulkUpdatesMySqlTest.Delete_with_LeftJoin
• NorthwindBulkUpdatesMySqlTest.Delete_with_LeftJoin_via_flattened_GroupJoin

Note: SQL assertions for Delete_with_LeftJoin and Delete_with_LeftJoin_via_flattened_GroupJoin are best-guess inferences from sibling tests. Please verify against an actual MySQL 8.0 run and adjust aliases if needed.

[Copilot]

Copilot review overview

🔵 Needs a closer look

Two SQL baselines are unverified and must be captured from a MySQL 8.0 test run.

Review effort: Lite
Findings: None

What changed in this PR

Fixes MySQL Error 1093 for ExecuteDeleteAsync queries using navigation-property predicates.

Changes:

• Allows LEFT JOIN expressions in delete translation.
• Updates bulk-delete SQL expectations.
• Requires verification of two inferred SQL baselines against MySQL 8.0.

File	Summary
test/​EFCore.MySql.FunctionalTests/​BulkUpdates/​NorthwindBulkUpdatesMySqlTest.cs	Updates navigation and left-join delete assertions.
test/​EFCore.MySql.FunctionalTests/​BulkUpdates/​NonSharedModelBulkUpdatesMySqlTest.cs	Updates optional-navigation delete expectations.
src/​EFCore.MySql/​Query/​Internal/​MySqlQueryableMethodTranslatingExpressionVisitor.cs	Enables delete translation with left joins.

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