From aaa219b1d96a173a541dcf130a000e155d02d283 Mon Sep 17 00:00:00 2001
From: devgor88 <devgordevgor@mail.ru>
Date: Tue, 10 Dec 2024 22:41:41 +0300
Subject: [PATCH] feat: [MariaDB] Support RETURNING clause (#2330)

* feat: implement returning clause for MariaDB

* fix: clean ReturningTests

* fix: docs update
---
 .../topics/DSL-CRUD-operations.topic          |  1 +
 .../exposed/sql/vendors/MariaDBDialect.kt     | 12 ++++++++
 .../sql/tests/shared/dml/ReturningTests.kt    | 30 ++++++++++---------
 3 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/documentation-website/Writerside/topics/DSL-CRUD-operations.topic b/documentation-website/Writerside/topics/DSL-CRUD-operations.topic
index 0fba69a6c2..f00ea9e957 100644
--- a/documentation-website/Writerside/topics/DSL-CRUD-operations.topic
+++ b/documentation-website/Writerside/topics/DSL-CRUD-operations.topic
@@ -406,6 +406,7 @@
             <p>Supported on: PostgreSQL and SQLite</p>
         </tldr>
         <p>Some databases allow the return of additional data every time a row is either inserted, updated, or deleted.
+            Please note that MariaDB only allows the return of this data for insertions and deletions.
             This can be accomplished by using one of the following functions:
         </p>
         <list>
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/MariaDBDialect.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/MariaDBDialect.kt
index 4299efb852..623627f3e1 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/MariaDBDialect.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/MariaDBDialect.kt
@@ -48,6 +48,18 @@ internal object MariaDBFunctionProvider : MysqlFunctionProvider() {
             sql
         }
     }
+
+    override fun returning(
+        mainSql: String,
+        returning: List<Expression<*>>,
+        transaction: Transaction
+    ): String {
+        return with(QueryBuilder(true)) {
+            +"$mainSql RETURNING "
+            returning.appendTo { +it }
+            toString()
+        }
+    }
 }
 
 /**
diff --git a/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/dml/ReturningTests.kt b/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/dml/ReturningTests.kt
index a6cd0b0d2b..422a3402f1 100644
--- a/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/dml/ReturningTests.kt
+++ b/exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/dml/ReturningTests.kt
@@ -17,7 +17,8 @@ import kotlin.test.assertIs
 import kotlin.test.assertTrue
 
 class ReturningTests : DatabaseTestsBase() {
-    private val returningSupportedDb = TestDB.ALL_POSTGRES.toSet() + TestDB.SQLITE
+    private val updateReturningSupportedDb = TestDB.ALL_POSTGRES.toSet() + TestDB.SQLITE
+    private val returningSupportedDb = updateReturningSupportedDb + TestDB.MARIADB
 
     object Items : IntIdTable("items") {
         val name = varchar("name", 32)
@@ -89,7 +90,7 @@ class ReturningTests : DatabaseTestsBase() {
 
     @Test
     fun testUpsertReturning() {
-        withTables(TestDB.ALL - returningSupportedDb, Items) {
+        withTables(TestDB.ALL - returningSupportedDb, Items) { testDB ->
             // return all columns by default
             val result1 = Items.upsertReturning {
                 it[name] = "A"
@@ -110,17 +111,18 @@ class ReturningTests : DatabaseTestsBase() {
             assertEquals("A", result2[Items.name])
             assertEquals(990.0, result2[Items.price])
 
-            val result3 = Items.upsertReturning(
-                returning = listOf(Items.name),
-                onUpdateExclude = listOf(Items.price),
-                where = { Items.price greater 500.0 }
-            ) {
-                it[id] = 1
-                it[name] = "B"
-                it[price] = 200.0
-            }.single()
-            assertEquals("B", result3[Items.name])
-
+            if (testDB != TestDB.MARIADB) {
+                val result3 = Items.upsertReturning(
+                    returning = listOf(Items.name),
+                    onUpdateExclude = listOf(Items.price),
+                    where = { Items.price greater 500.0 }
+                ) {
+                    it[id] = 1
+                    it[name] = "B"
+                    it[price] = 200.0
+                }.single()
+                assertEquals("B", result3[Items.name])
+            }
             assertEquals(1, Items.selectAll().count())
         }
     }
@@ -196,7 +198,7 @@ class ReturningTests : DatabaseTestsBase() {
 
     @Test
     fun testUpdateReturning() {
-        withTables(TestDB.enabledDialects() - returningSupportedDb, Items) {
+        withTables(TestDB.enabledDialects() - updateReturningSupportedDb, Items) {
             val input = listOf("A" to 99.0, "B" to 100.0, "C" to 200.0)
             Items.batchInsert(input) { (n, p) ->
                 this[Items.name] = n