Merge pull request #213 from microting/copilot/fix-target-table-update-error

Handle MySQL/MariaDB DELETE with self-referencing subquery limitation

Author: renemadsen

src/EFCore.MySql/Infrastructure/MariaDbServerVersion.cs

@@ -99,6 +99,7 @@ internal MariaDbServerVersionSupport([NotNull] ServerVersion serverVersion)
             public override bool WhereSubqueryReferencesOuterQuery => false;
             public override bool FieldReferenceInTableValueConstructor => false;
             public override bool CollationCharacterSetApplicabilityWithFullCollationNameColumn => ServerVersion.Version >= new Version(10, 10, 1);
+            public override bool DeleteWithSelfReferencingSubquery => ServerVersion.Version >= new Version(11, 0, 0); // MariaDB 11+ supports DELETE with self-referencing subqueries
 
             public override bool JsonTableImplementationStable => false;
             public override bool JsonTableImplementationWithoutMariaDbBugs => false;

src/EFCore.MySql/Infrastructure/MySqlServerVersion.cs

@@ -101,6 +101,7 @@ internal MySqlServerVersionSupport([NotNull] ServerVersion serverVersion)
             public override bool WhereSubqueryReferencesOuterQuery => false;
             public override bool FieldReferenceInTableValueConstructor => true;
             public override bool CollationCharacterSetApplicabilityWithFullCollationNameColumn => false;
+            public override bool DeleteWithSelfReferencingSubquery => false; // MySQL does not support DELETE with self-referencing subqueries (Error 1093)
 
             public override bool JsonTableImplementationStable => false;
             public override bool JsonTableImplementationWithoutMySqlBugs => false; // Other non-fatal bugs regarding JSON_TABLE.

src/EFCore.MySql/Infrastructure/ServerVersionSupport.cs

@@ -97,6 +97,7 @@ public virtual bool PropertyOrVersion(string propertyNameOrServerVersion)
         public virtual bool WhereSubqueryReferencesOuterQuery => false;
         public virtual bool FieldReferenceInTableValueConstructor => false;
         public virtual bool CollationCharacterSetApplicabilityWithFullCollationNameColumn => false;
+        public virtual bool DeleteWithSelfReferencingSubquery => false;
 
         public virtual bool JsonTableImplementationStable => JsonTable;
         public virtual bool JsonTableImplementationWithoutMySqlBugs => JsonTable;

test/EFCore.MySql.FunctionalTests/BulkUpdates/NorthwindBulkUpdatesMySqlTest.cs

@@ -554,9 +554,39 @@ LIMIT @p0 OFFSET @p
 
     public override async Task Delete_with_LeftJoin(bool async)
     {
-        await base.Delete_with_LeftJoin(async);
+        if (!AppConfig.ServerVersion.Supports.DeleteWithSelfReferencingSubquery)
+        {
+            // Not supported by MySQL and older MariaDB versions:
+            //     Error Code: 1093. You can't specify target table 'o' for update in FROM clause
+            await Assert.ThrowsAsync<MySqlException>(
+                () => base.Delete_with_LeftJoin(async));
 
-        AssertSql(
+            AssertSql(
+"""
+@p0='100'
+@p='0'
+
+DELETE `o`
+FROM `Order Details` AS `o`
+WHERE EXISTS (
+    SELECT 1
+    FROM `Order Details` AS `o0`
+    LEFT JOIN (
+        SELECT `o2`.`OrderID`
+        FROM `Orders` AS `o2`
+        WHERE `o2`.`OrderID` < 10300
+        ORDER BY `o2`.`OrderID`
+        LIMIT @p0 OFFSET @p
+    ) AS `o1` ON `o0`.`OrderID` = `o1`.`OrderID`
+    WHERE (`o0`.`OrderID` < 10276) AND ((`o0`.`OrderID` = `o`.`OrderID`) AND (`o0`.`ProductID` = `o`.`ProductID`)))
+""");
+        }
+        else
+        {
+            // Works as expected in MariaDB 11+.
+            await base.Delete_with_LeftJoin(async);
+
+            AssertSql(
 """
 @p0='100'
 @p='0'
@@ -575,6 +605,7 @@ LIMIT @p0 OFFSET @p
     ) AS `o1` ON `o0`.`OrderID` = `o1`.`OrderID`
     WHERE (`o0`.`OrderID` < 10276) AND ((`o0`.`OrderID` = `o`.`OrderID`) AND (`o0`.`ProductID` = `o`.`ProductID`)))
 """);
+        }
     }
 
     public override async Task Delete_with_cross_join(bool async)
@@ -989,7 +1020,7 @@ await Assert.ThrowsAsync<MySqlException>(
         }
         else
         {
-            // Works as expected in MariaDB.
+            // Works as expected in MariaDB (all versions).
             await base.Update_Where_GroupBy_First_set_constant_3(async);
 
             AssertExecuteUpdateSql(
@@ -1555,7 +1586,18 @@ public override async Task Update_with_two_inner_joins(bool async)
 
     public override async Task Delete_with_LeftJoin_via_flattened_GroupJoin(bool async)
     {
-        await base.Delete_with_LeftJoin_via_flattened_GroupJoin(async);
+        if (!AppConfig.ServerVersion.Supports.DeleteWithSelfReferencingSubquery)
+        {
+            // Not supported by MySQL and older MariaDB versions:
+            //     Error Code: 1093. You can't specify target table 'o' for update in FROM clause
+            await Assert.ThrowsAsync<MySqlException>(
+                () => base.Delete_with_LeftJoin_via_flattened_GroupJoin(async));
+        }
+        else
+        {
+            // Works as expected in MariaDB 11+.
+            await base.Delete_with_LeftJoin_via_flattened_GroupJoin(async);
+        }
 
         // Note: SQL validation skipped - actual SQL needs to be captured from test run
     }

test/EFCore.MySql.FunctionalTests/BulkUpdates/TPHFiltersInheritanceBulkUpdatesMySqlTest.cs

@@ -94,8 +94,7 @@ public override async Task Delete_GroupBy_Where_Select_First_2(bool async)
 
     public override async Task Delete_GroupBy_Where_Select_First_3(bool async)
     {
-        if (AppConfig.ServerVersion.Type == ServerType.MariaDb &&
-            AppConfig.ServerVersion.Version >= new Version(11, 1))
+        if (AppConfig.ServerVersion.Supports.DeleteWithSelfReferencingSubquery)
         {
             await base.Delete_GroupBy_Where_Select_First_3(async);
 
@@ -118,7 +117,7 @@ HAVING COUNT(*) < 3
         }
         else
         {
-            // Not supported by MySQL:
+            // Not supported by MySQL and older MariaDB versions:
             //     Error Code: 1093. You can't specify target table 'c' for update in FROM clause
             await Assert.ThrowsAsync<MySqlException>(
                 () => base.Delete_GroupBy_Where_Select_First_3(async));