Fix Assert.Empty() failures for LATERAL join tests on MySQL 8.0.14+

[Copilot]

Two correlated collection tests were failing on MySQL 8.0.40 with Assert.Empty() Failure: Collection was not empty because SQL was being generated when tests expected none. MariaDB tests were skipped (OuterApply unsupported).

Root Cause

MySQL 8.0.14+ supports OUTER APPLY via LATERAL joins. The query translator generates valid SQL:

SELECT `c`.`CustomerID`, `s`.`First`, `s`.`Second`, `s`.`Third`
FROM `Customers` AS `c`
LEFT JOIN LATERAL (
    SELECT DISTINCT `o`.`OrderID` AS `First`, `o`.`OrderDate` AS `Second`, `c0`.`City` AS `Third`
    FROM `Orders` AS `o`
    LEFT JOIN `Customers` AS `c0` ON `o`.`CustomerID` = `c0`.`CustomerID`
    WHERE `c`.`CustomerID` = `o`.`CustomerID`
) AS `s` ON TRUE
ORDER BY `c`.`CustomerID`, `s`.`First`, `s`.`Second`

MariaDB never supports OuterApply (all versions), causing translation failures and test skips.

Changes

• Added version-conditional SQL assertions using AppConfig.ServerVersion.Supports.OuterApply

  • MySQL 8.0.14+: Assert expected LATERAL SQL
  • MariaDB: Assert no SQL (tests skip on translation failure)

• Updated tests:

  • Correlated_collection_with_distinct_without_default_identifiers_projecting_columns
  • Correlated_collection_with_distinct_without_default_identifiers_projecting_columns_with_navigation

if (AppConfig.ServerVersion.Supports.OuterApply)
{
    AssertSql(/* LATERAL SQL */);
}
else
{
    AssertSql(); // No SQL - will skip
}

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Assert.Empty() Failure: Collection was not empty</issue_title>
<issue_description>With respect to the difference in MySQL and Mariadb, this is broken for MySQL v8.0.40, MariaDB 10.5.27, but it works in MariaDB 11.6.2:

Failed Pomelo.EntityFrameworkCore.MySql.FunctionalTests.Query.NorthwindMiscellaneousQueryMySqlTest.Correlated_collection_with_distinct_without_default_identifiers_projecting_columns_with_navigation(async: False) [1 s]
Error Message:
Assert.Empty() Failure: Collection was not empty
Collection: ["SELECT c.CustomerID, s.First, s.Second"···]
Stack Trace:
at Microsoft.EntityFrameworkCore.TestUtilities.TestSqlLoggerFactory.AssertBaseline(String[] expected, Boolean assertOrder, Boolean forUpdate)
at Pomelo.EntityFrameworkCore.MySql.FunctionalTests.Query.NorthwindMiscellaneousQueryMySqlTest.AssertSql(String[] expected) in /home/runner/work/Pomelo.EntityFrameworkCore.MySql/Pomelo.EntityFrameworkCore.MySql/test/EFCore.MySql.FunctionalTests/Query/NorthwindMiscellaneousQueryMySqlTest.cs:line 7244
at Pomelo.EntityFrameworkCore.MySql.FunctionalTests.Query.NorthwindMiscellaneousQueryMySqlTest.Correlated_collection_with_distinct_without_default_identifiers_projecting_columns_with_navigation(Boolean async) in /home/runner/work/Pomelo.EntityFrameworkCore.MySql/Pomelo.EntityFrameworkCore.MySql/test/EFCore.MySql.FunctionalTests/Query/NorthwindMiscellaneousQueryMySqlTest.cs:line 6836
--- End of stack trace from previous location ---

Failed Pomelo.EntityFrameworkCore.MySql.FunctionalTests.Query.NorthwindMiscellaneousQueryMySqlTest.Correlated_collection_with_distinct_without_default_identifiers_projecting_columns_with_navigation(async: True) [2 s]
Error Message:
Assert.Empty() Failure: Collection was not empty
Collection: ["SELECT c.CustomerID, s.First, s.Second"···]
Stack Trace:
at Microsoft.EntityFrameworkCore.TestUtilities.TestSqlLoggerFactory.AssertBaseline(String[] expected, Boolean assertOrder, Boolean forUpdate)
at Pomelo.EntityFrameworkCore.MySql.FunctionalTests.Query.NorthwindMiscellaneousQueryMySqlTest.AssertSql(String[] expected) in /home/runner/work/Pomelo.EntityFrameworkCore.MySql/Pomelo.EntityFrameworkCore.MySql/test/EFCore.MySql.FunctionalTests/Query/NorthwindMiscellaneousQueryMySqlTest.cs:line 7244
at Pomelo.EntityFrameworkCore.MySql.FunctionalTests.Query.NorthwindMiscellaneousQueryMySqlTest.Correlated_collection_with_distinct_without_default_identifiers_projecting_columns_with_navigation(Boolean async) in /home/runner/work/Pomelo.EntityFrameworkCore.MySql/Pomelo.EntityFrameworkCore.MySql/test/EFCore.MySql.FunctionalTests/Query/NorthwindMiscellaneousQueryMySqlTest.cs:line 6836
--- End of stack trace from previous location ---
```</issue_description>

<agent_instructions>restore, build, ensure database is running before testing, fix code, restest before committing</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes Assert.Empty() Failure: Collection was not empty #218

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