From df75b2452a72adfc473772c37342c75e7e731d50 Mon Sep 17 00:00:00 2001
From: Kristofer Pervin <7747148+kpervin@users.noreply.github.com>
Date: Thu, 14 Dec 2023 16:32:25 -0400
Subject: [PATCH] feat(mysql): support `order by nulls first/last` (#5021)

- Added `getOrderByExpression` to AbstractSqlPlatform.ts as an
overridable method to format `orderBy` queries. This uses syntax that is
recognized by both SQLite and PostGreSQL
- Added override of `getOrderByExpression` to MariaDbPlatform.ts and
MySqlPlatform.ts that adds functionality to handle `(ASC|DESC) NULLS
(FIRST|LAST)` syntax

Closes #5004
---
 packages/knex/src/AbstractSqlPlatform.ts      |  7 +++++
 packages/knex/src/query/QueryBuilderHelper.ts |  2 +-
 packages/mariadb/src/MariaDbPlatform.ts       | 23 +++++++++++++++-
 packages/mysql/src/MySqlPlatform.ts           | 26 ++++++++++++++++++-
 tests/QueryBuilder.test.ts                    |  4 +--
 5 files changed, 57 insertions(+), 5 deletions(-)

diff --git a/packages/knex/src/AbstractSqlPlatform.ts b/packages/knex/src/AbstractSqlPlatform.ts
index c4d93eb33c3e..0090a3eea5f6 100644
--- a/packages/knex/src/AbstractSqlPlatform.ts
+++ b/packages/knex/src/AbstractSqlPlatform.ts
@@ -135,4 +135,11 @@ export abstract class AbstractSqlPlatform extends Platform {
     return ret + 'else null end)';
   }
 
+  /**
+   * @internal
+   */
+  getOrderByExpression(column: string, direction: string): string[] {
+    return [ `${column} ${direction.toLowerCase()}` ];
+  }
+
 }
diff --git a/packages/knex/src/query/QueryBuilderHelper.ts b/packages/knex/src/query/QueryBuilderHelper.ts
index b94692feae25..e87c764c3b9e 100644
--- a/packages/knex/src/query/QueryBuilderHelper.ts
+++ b/packages/knex/src/query/QueryBuilderHelper.ts
@@ -638,7 +638,7 @@ export class QueryBuilderHelper {
         if (Array.isArray(order)) {
           order.forEach(part => ret.push(...this.getQueryOrderFromObject(type, part, populate)));
         } else {
-          ret.push(`${colPart} ${order.toLowerCase()}`);
+          ret.push(...this.platform.getOrderByExpression(colPart, order));
         }
       }
     }
diff --git a/packages/mariadb/src/MariaDbPlatform.ts b/packages/mariadb/src/MariaDbPlatform.ts
index 9b4b370c9fb0..3f95f97916ad 100644
--- a/packages/mariadb/src/MariaDbPlatform.ts
+++ b/packages/mariadb/src/MariaDbPlatform.ts
@@ -1,4 +1,4 @@
-import { AbstractSqlPlatform } from '@mikro-orm/knex';
+import { AbstractSqlPlatform, QueryOrder } from '@mikro-orm/knex';
 import { MariaDbSchemaHelper } from './MariaDbSchemaHelper';
 import { MariaDbExceptionConverter } from './MariaDbExceptionConverter';
 import { Utils, type SimpleColumnMeta, type Dictionary, type Type } from '@mikro-orm/core';
@@ -74,4 +74,25 @@ export class MariaDbPlatform extends AbstractSqlPlatform {
     return `alter table ${quotedTableName} add fulltext index ${quotedIndexName}(${quotedColumnNames.join(',')})`;
   }
 
+  private readonly ORDER_BY_NULLS_TRANSLATE = {
+    [QueryOrder.asc_nulls_first]: 'is not null',
+    [QueryOrder.asc_nulls_last]: 'is null',
+    [QueryOrder.desc_nulls_first]: 'is not null',
+    [QueryOrder.desc_nulls_last]: 'is null',
+  } as const;
+
+  /* istanbul ignore next */
+  override getOrderByExpression(column: string, direction: string): string[] {
+    const ret: string[] = [];
+    const dir = direction.toLowerCase() as keyof typeof this.ORDER_BY_NULLS_TRANSLATE;
+
+    if (dir in this.ORDER_BY_NULLS_TRANSLATE) {
+      ret.push(`${column} ${this.ORDER_BY_NULLS_TRANSLATE[dir]}`);
+    }
+
+    ret.push(`${column} ${dir.replace(/(\s|nulls|first|last)*/gi, '')}`);
+
+    return ret;
+  }
+
 }
diff --git a/packages/mysql/src/MySqlPlatform.ts b/packages/mysql/src/MySqlPlatform.ts
index 73cfeed470d6..d8bb92cbfef9 100644
--- a/packages/mysql/src/MySqlPlatform.ts
+++ b/packages/mysql/src/MySqlPlatform.ts
@@ -1,4 +1,8 @@
-import { AbstractSqlPlatform, type IndexDef } from '@mikro-orm/knex';
+import {
+  AbstractSqlPlatform,
+  type IndexDef,
+  QueryOrder,
+} from '@mikro-orm/knex';
 import { MySqlSchemaHelper } from './MySqlSchemaHelper';
 import { MySqlExceptionConverter } from './MySqlExceptionConverter';
 import { Utils, type SimpleColumnMeta, type Dictionary, type Type, type TransformContext } from '@mikro-orm/core';
@@ -88,4 +92,24 @@ export class MySqlPlatform extends AbstractSqlPlatform {
     return `alter table ${quotedTableName} add fulltext index ${quotedIndexName}(${quotedColumnNames.join(',')})`;
   }
 
+  private readonly ORDER_BY_NULLS_TRANSLATE = {
+    [QueryOrder.asc_nulls_first]: 'is not null',
+    [QueryOrder.asc_nulls_last]: 'is null',
+    [QueryOrder.desc_nulls_first]: 'is not null',
+    [QueryOrder.desc_nulls_last]: 'is null',
+  } as const;
+
+  override getOrderByExpression(column: string, direction: string): string[] {
+    const ret: string[] = [];
+    const dir = direction.toLowerCase() as keyof typeof this.ORDER_BY_NULLS_TRANSLATE;
+
+    if (dir in this.ORDER_BY_NULLS_TRANSLATE) {
+      ret.push(`${column} ${this.ORDER_BY_NULLS_TRANSLATE[dir]}`);
+    }
+
+    ret.push(`${column} ${dir.replace(/(\s|nulls|first|last)*/gi, '')}`);
+
+    return ret;
+  }
+
 }
diff --git a/tests/QueryBuilder.test.ts b/tests/QueryBuilder.test.ts
index cb62453a3ba2..07ba6996076d 100644
--- a/tests/QueryBuilder.test.ts
+++ b/tests/QueryBuilder.test.ts
@@ -2207,13 +2207,13 @@ describe('QueryBuilder', () => {
   test('order by asc nulls first', async () => {
     const qb = orm.em.createQueryBuilder(Publisher2);
     qb.select('*').orderBy({ name: QueryOrder.ASC_NULLS_FIRST });
-    expect(qb.getQuery()).toEqual('select `e0`.* from `publisher2` as `e0` order by `e0`.`name` asc nulls first');
+    expect(qb.getQuery()).toEqual('select `e0`.* from `publisher2` as `e0` order by `e0`.`name` is not null, `e0`.`name` asc');
   });
 
   test('order by nulls last', async () => {
     const qb = orm.em.createQueryBuilder(Publisher2);
     qb.select('*').orderBy({ name: QueryOrder.DESC_NULLS_LAST, type: QueryOrder.ASC_NULLS_LAST });
-    expect(qb.getQuery()).toEqual('select `e0`.* from `publisher2` as `e0` order by `e0`.`name` desc nulls last, `e0`.`type` asc nulls last');
+    expect(qb.getQuery()).toEqual('select `e0`.* from `publisher2` as `e0` order by `e0`.`name` is null, `e0`.`name` desc, `e0`.`type` is null, `e0`.`type` asc');
   });
 
   test('order by custom expression', async () => {