diff --git a/src/Driver/AbstractMySQLDriver.php b/src/Driver/AbstractMySQLDriver.php
index 5d33e04e4ad..4610bde3bd8 100644
--- a/src/Driver/AbstractMySQLDriver.php
+++ b/src/Driver/AbstractMySQLDriver.php
@@ -12,6 +12,7 @@
 use Doctrine\DBAL\Platforms\MariaDB1052Platform;
 use Doctrine\DBAL\Platforms\MariaDB1060Platform;
 use Doctrine\DBAL\Platforms\MariaDBPlatform;
+use Doctrine\DBAL\Platforms\MySQL8013Platform;
 use Doctrine\DBAL\Platforms\MySQL80Platform;
 use Doctrine\DBAL\Platforms\MySQL84Platform;
 use Doctrine\DBAL\Platforms\MySQLPlatform;
@@ -58,6 +59,10 @@ public function getDatabasePlatform(ServerVersionProvider $versionProvider): Abs
             return new MySQL84Platform();
         }
 
+        if (version_compare($version, '8.0.13', '>=')) {
+            return new MySQL8013Platform();
+        }
+
         if (version_compare($version, '8.0.0', '>=')) {
             return new MySQL80Platform();
         }
diff --git a/src/Platforms/AbstractMySQLPlatform.php b/src/Platforms/AbstractMySQLPlatform.php
index 770d86341ef..4c72aca26dc 100644
--- a/src/Platforms/AbstractMySQLPlatform.php
+++ b/src/Platforms/AbstractMySQLPlatform.php
@@ -43,6 +43,11 @@ abstract class AbstractMySQLPlatform extends AbstractPlatform
     final public const LENGTH_LIMIT_BLOB       = 65535;
     final public const LENGTH_LIMIT_MEDIUMBLOB = 16777215;
 
+    public function getColumnNameForIndexFetch(): string
+    {
+        return 'COLUMN_NAME';
+    }
+
     protected function doModifyLimitQuery(string $query, ?int $limit, int $offset): string
     {
         if ($limit !== null) {
diff --git a/src/Platforms/AbstractPlatform.php b/src/Platforms/AbstractPlatform.php
index b9c5fa2d19d..d2128186c56 100644
--- a/src/Platforms/AbstractPlatform.php
+++ b/src/Platforms/AbstractPlatform.php
@@ -55,8 +55,10 @@
 use function str_contains;
 use function str_replace;
 use function strlen;
+use function strrpos;
 use function strtolower;
 use function strtoupper;
+use function substr;
 
 /**
  * Base class for all DatabasePlatforms. The DatabasePlatforms are the central
@@ -794,6 +796,16 @@ private function buildCreateTableSQL(Table $table, bool $createForeignKeys): arr
         $options['primary']           = [];
 
         foreach ($table->getIndexes() as $index) {
+            if ($index->isFunctional() && ! $this->supportsFunctionalIndex()) {
+                throw new InvalidArgumentException(sprintf(
+                    'Index "%s" on table "%s" contains a functional part, ' .
+                    'but platform "%s" does not support functional indexes.',
+                    $index->getName(),
+                    $table->getName(),
+                    get_debug_type($this),
+                ));
+            }
+
             if (! $index->isPrimary()) {
                 $options['indexes'][$index->getQuotedName($this)] = $index;
 
@@ -1081,6 +1093,16 @@ public function getCreateIndexSQL(Index $index, string $table): string
             ));
         }
 
+        if ($index->isFunctional() && ! $this->supportsFunctionalIndex()) {
+            throw new InvalidArgumentException(sprintf(
+                'Index "%s" on table "%s" contains a functional part, ' .
+                'but platform "%s" does not support functional indexes.',
+                $name,
+                $table,
+                get_debug_type($this),
+            ));
+        }
+
         if ($index->isPrimary()) {
             return $this->getCreatePrimaryKeySQL($index, $table);
         }
@@ -1533,6 +1555,15 @@ public function getIndexDeclarationSQL(Index $index): string
             throw new InvalidArgumentException('Incomplete definition. "columns" required.');
         }
 
+        if ($index->isFunctional() && ! $this->supportsFunctionalIndex()) {
+            throw new InvalidArgumentException(sprintf(
+                'Index "%s" contains a functional part, ' .
+                'but platform "%s" does not support functional indexes.',
+                $index->getName(),
+                get_debug_type($this),
+            ));
+        }
+
         return $this->getCreateIndexSQLFlags($index) . 'INDEX ' . $index->getQuotedName($this)
             . ' (' . implode(', ', $index->getQuotedColumns($this)) . ')' . $this->getPartialIndexSQL($index);
     }
@@ -1973,6 +2004,14 @@ public function supportsColumnCollation(): bool
         return false;
     }
 
+    /**
+     * A flag that indicates whether the platform supports functional indexes.
+     */
+    public function supportsFunctionalIndex(): bool
+    {
+        return false;
+    }
+
     /**
      * Gets the format string, as accepted by the date() function, that describes
      * the format of a stored datetime value of this platform.
diff --git a/src/Platforms/MySQL8013Platform.php b/src/Platforms/MySQL8013Platform.php
new file mode 100644
index 00000000000..2b2feaf0428
--- /dev/null
+++ b/src/Platforms/MySQL8013Platform.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\DBAL\Platforms;
+
+/**
+ * Provides features of the MySQL since 8.0.13 database platform.
+ *
+ * Note: Should not be used with versions prior to 8.0.13.
+ * @deprecated This class will be removed once support for MySQL 8.0.13 is dropped.
+ */
+class MySQL8013Platform extends MySQL80Platform
+{
+    public function getColumnNameForIndexFetch(): string
+    {
+        return "COALESCE(COLUMN_NAME, CONCAT('(', REPLACE(EXPRESSION, '\\\''', ''''), ')'))";
+    }
+
+    public function supportsFunctionalIndex(): bool
+    {
+        return true;
+    }
+}
diff --git a/src/Platforms/MySQL84Platform.php b/src/Platforms/MySQL84Platform.php
index 0c304318c62..15d0083840f 100644
--- a/src/Platforms/MySQL84Platform.php
+++ b/src/Platforms/MySQL84Platform.php
@@ -16,4 +16,9 @@ protected function createReservedKeywordsList(): KeywordList
     {
         return new MySQL84Keywords();
     }
+
+    public function supportsFunctionalIndex(): bool
+    {
+        return true;
+    }
 }
diff --git a/src/Platforms/PostgreSQLPlatform.php b/src/Platforms/PostgreSQLPlatform.php
index 166ee7547fb..df8e0eaaa68 100644
--- a/src/Platforms/PostgreSQLPlatform.php
+++ b/src/Platforms/PostgreSQLPlatform.php
@@ -781,4 +781,9 @@ public function createSchemaManager(Connection $connection): PostgreSQLSchemaMan
     {
         return new PostgreSQLSchemaManager($connection, $this);
     }
+
+    public function supportsFunctionalIndex(): bool
+    {
+        return true;
+    }
 }
diff --git a/src/Platforms/SQLitePlatform.php b/src/Platforms/SQLitePlatform.php
index 8ba836406d0..3144747a1f5 100644
--- a/src/Platforms/SQLitePlatform.php
+++ b/src/Platforms/SQLitePlatform.php
@@ -35,6 +35,7 @@
 use function sprintf;
 use function str_replace;
 use function strpos;
+use function strrpos;
 use function strtolower;
 use function substr;
 use function trim;
@@ -561,6 +562,16 @@ public function getCreateIndexSQL(Index $index, string $table): string
             ));
         }
 
+        if ($index->isFunctional() && ! $this->supportsFunctionalIndex()) {
+            throw new InvalidArgumentException(sprintf(
+                'Index "%s" on table "%s" contains a functional part, ' .
+                'but platform "%s" does not support functional indexes.',
+                $name,
+                $table,
+                get_debug_type($this),
+            ));
+        }
+
         if ($index->isPrimary()) {
             return $this->getCreatePrimaryKeySQL($index, $table);
         }
diff --git a/src/Schema/Index.php b/src/Schema/Index.php
index 175565483d1..9803f9c7676 100644
--- a/src/Schema/Index.php
+++ b/src/Schema/Index.php
@@ -12,6 +12,8 @@
 use function array_search;
 use function array_shift;
 use function count;
+use function str_ends_with;
+use function str_starts_with;
 use function strtolower;
 
 class Index extends AbstractAsset
@@ -27,6 +29,8 @@ class Index extends AbstractAsset
 
     protected bool $_isPrimary = false;
 
+    protected bool $_isFunctional = false;
+
     /**
      * Platform specific flags for indexes.
      *
@@ -58,6 +62,10 @@ public function __construct(
 
         foreach ($columns as $column) {
             $this->_addColumn($column);
+
+            $this->_isFunctional = $this->_isFunctional === true
+                ? $this->_isFunctional
+                : self::isFunctionalIndex($column);
         }
 
         foreach ($flags as $flag) {
@@ -101,10 +109,14 @@ public function getQuotedColumns(AbstractPlatform $platform): array
         foreach ($this->_columns as $column) {
             $length = array_shift($subParts);
 
-            $quotedColumn = $column->getQuotedName($platform);
+            if ($this->isFunctional()) {
+                $quotedColumn = $column->getName();
+            } else {
+                $quotedColumn = $column->getQuotedName($platform);
 
-            if ($length !== null) {
-                $quotedColumn .= '(' . $length . ')';
+                if ($length !== null) {
+                    $quotedColumn .= '(' . $length . ')';
+                }
             }
 
             $columns[] = $quotedColumn;
@@ -137,6 +149,11 @@ public function isPrimary(): bool
         return $this->_isPrimary;
     }
 
+    public function isFunctional(): bool
+    {
+        return $this->_isFunctional;
+    }
+
     public function hasColumnAtPosition(string $name, int $pos = 0): bool
     {
         $name         = $this->trimQuotes(strtolower($name));
@@ -283,6 +300,11 @@ public function getOptions(): array
         return $this->options;
     }
 
+    public static function isFunctionalIndex(string $name): bool
+    {
+        return str_starts_with($name, '(') && str_ends_with($name, ')');
+    }
+
     /**
      * Return whether the two indexes have the same partial index
      */
diff --git a/src/Schema/MySQLSchemaManager.php b/src/Schema/MySQLSchemaManager.php
index fa042d653ce..40833e6314d 100644
--- a/src/Schema/MySQLSchemaManager.php
+++ b/src/Schema/MySQLSchemaManager.php
@@ -390,10 +390,12 @@ protected function selectIndexColumns(string $databaseName, ?string $tableName =
             $sql .= ' TABLE_NAME,';
         }
 
-        $sql .= <<<'SQL'
+        $columnName = $this->getColumnNameForIndexFetch();
+
+        $sql .= <<<SQL
         NON_UNIQUE  AS Non_Unique,
         INDEX_NAME  AS Key_name,
-        COLUMN_NAME AS Column_Name,
+        {$columnName},
         SUB_PART    AS Sub_Part,
         INDEX_TYPE  AS Index_Type
 FROM information_schema.STATISTICS
@@ -539,4 +541,17 @@ private function getDefaultTableOptions(): DefaultTableOptions
 
         return $this->defaultTableOptions;
     }
+
+    /**
+     * EXPRESSION
+     *
+     * MySQL 8.0.13 and higher supports functional key parts (see Functional Key Parts), which affects both
+     * the COLUMN_NAME and EXPRESSION columns:
+     * For a nonfunctional key part, COLUMN_NAME indicates the column indexed by the key part and EXPRESSION is NULL.
+     * For a functional key part, COLUMN_NAME column is NULL and EXPRESSION indicates the expression for the key part.
+     */
+    private function getColumnNameForIndexFetch(): string
+    {
+        return $this->platform->getColumnNameForIndexFetch() . ' as Column_Name';
+    }
 }
diff --git a/src/Schema/PostgreSQLSchemaManager.php b/src/Schema/PostgreSQLSchemaManager.php
index 9af16c9986a..f4ebfd82ab4 100644
--- a/src/Schema/PostgreSQLSchemaManager.php
+++ b/src/Schema/PostgreSQLSchemaManager.php
@@ -19,8 +19,8 @@
 use function implode;
 use function in_array;
 use function is_string;
+use function json_decode;
 use function preg_match;
-use function sprintf;
 use function str_contains;
 use function str_replace;
 use function strtolower;
@@ -161,30 +161,16 @@ protected function _getPortableTableIndexesList(array $tableIndexes, string $tab
     {
         $buffer = [];
         foreach ($tableIndexes as $row) {
-            $colNumbers    = array_map('intval', explode(' ', $row['indkey']));
-            $columnNameSql = sprintf(
-                'SELECT attnum, attname FROM pg_attribute WHERE attrelid=%d AND attnum IN (%s) ORDER BY attnum ASC',
-                $row['indrelid'],
-                implode(' ,', $colNumbers),
-            );
-
-            $indexColumns = $this->connection->fetchAllAssociative($columnNameSql);
-
-            // required for getting the order of the columns right.
-            foreach ($colNumbers as $colNum) {
-                foreach ($indexColumns as $colRow) {
-                    if ($colNum !== $colRow['attnum']) {
-                        continue;
-                    }
-
-                    $buffer[] = [
-                        'key_name' => $row['relname'],
-                        'column_name' => trim($colRow['attname']),
-                        'non_unique' => ! $row['indisunique'],
-                        'primary' => $row['indisprimary'],
-                        'where' => $row['where'],
-                    ];
-                }
+            $indexColumns = json_decode($row['index_columns'], true, flags: JSON_THROW_ON_ERROR);
+
+            foreach ($indexColumns as $colRow) {
+                $buffer[] = [
+                    'key_name' => $row['relname'],
+                    'column_name' => trim($colRow),
+                    'non_unique' => ! $row['indisunique'],
+                    'primary' => $row['indisprimary'],
+                    'where' => $row['where'],
+                ];
             }
         }
 
@@ -468,34 +454,53 @@ protected function selectTableColumns(string $databaseName, ?string $tableName =
 
     protected function selectIndexColumns(string $databaseName, ?string $tableName = null): Result
     {
-        $sql = 'SELECT';
-
+        $tableNameSql = '';
         if ($tableName === null) {
-            $sql .= ' tc.relname AS table_name, tn.nspname AS schema_name,';
+            $tableNameSql = <<<'SQL'
+                tc.relname AS table_name,
+                tn.nspname AS schema_name,
+            SQL;
         }
 
-        $sql .= <<<'SQL'
-                   quote_ident(ic.relname) AS relname,
-                   i.indisunique,
-                   i.indisprimary,
-                   i.indkey,
-                   i.indrelid,
-                   pg_get_expr(indpred, indrelid) AS "where"
-              FROM pg_index i
-                   JOIN pg_class AS tc ON tc.oid = i.indrelid
-                   JOIN pg_namespace tn ON tn.oid = tc.relnamespace
-                   JOIN pg_class AS ic ON ic.oid = i.indexrelid
-             WHERE ic.oid IN (
-                SELECT indexrelid
-                FROM pg_index i, pg_class c, pg_namespace n
-SQL;
-
-        $conditions = array_merge([
-            'c.oid = i.indrelid',
-            'c.relnamespace = n.oid',
-        ], $this->buildQueryConditions($tableName));
+        $whereConditions = array_merge(
+            [
+                'c.oid = i.indrelid',
+                'c.relnamespace = n.oid',
+            ],
+            $this->buildQueryConditions($tableName),
+        );
 
-        $sql .= ' WHERE ' . implode(' AND ', $conditions) . ')';
+        $whereSql = implode(' AND ', $whereConditions);
+
+        $sql = <<<SQL
+            SELECT
+                {$tableNameSql}
+                quote_ident(ic.relname) AS relname,
+                i.indisunique,
+                i.indisprimary,
+                i.indkey,
+                i.indrelid,
+                pg_get_expr(indpred, indrelid) AS "where",
+                (
+                     SELECT
+                         json_agg(
+                             pg_get_indexdef(i.indexrelid, a.attnum, true)
+                         ) as index_columns
+                     FROM pg_attribute AS a
+                     WHERE a.attrelid = ic.oid
+                )
+            FROM pg_index i
+            JOIN pg_class AS tc ON tc.oid = i.indrelid
+            JOIN pg_namespace tn ON tn.oid = tc.relnamespace
+            JOIN pg_class AS ic ON ic.oid = i.indexrelid
+            WHERE ic.oid IN (
+                SELECT indexrelid
+                FROM pg_index i,
+                     pg_class c,
+                     pg_namespace n
+                WHERE {$whereSql}
+            )
+        SQL;
 
         return $this->connection->executeQuery($sql);
     }
diff --git a/src/Schema/Table.php b/src/Schema/Table.php
index cc7f04d2c49..d34b66ab169 100644
--- a/src/Schema/Table.php
+++ b/src/Schema/Table.php
@@ -743,7 +743,7 @@ private function _createIndex(
         }
 
         foreach ($columns as $columnName) {
-            if (! $this->hasColumn($columnName)) {
+            if (! $this->hasColumn($columnName) && ! Index::isFunctionalIndex($columnName)) {
                 throw ColumnDoesNotExist::new($columnName, $this->_name);
             }
         }
diff --git a/tests/Driver/VersionAwarePlatformDriverTest.php b/tests/Driver/VersionAwarePlatformDriverTest.php
index 3996e4691d1..11478a0c58c 100644
--- a/tests/Driver/VersionAwarePlatformDriverTest.php
+++ b/tests/Driver/VersionAwarePlatformDriverTest.php
@@ -10,6 +10,7 @@
 use Doctrine\DBAL\Platforms\MariaDB1052Platform;
 use Doctrine\DBAL\Platforms\MariaDB1060Platform;
 use Doctrine\DBAL\Platforms\MariaDBPlatform;
+use Doctrine\DBAL\Platforms\MySQL8013Platform;
 use Doctrine\DBAL\Platforms\MySQL80Platform;
 use Doctrine\DBAL\Platforms\MySQL84Platform;
 use Doctrine\DBAL\Platforms\MySQLPlatform;
@@ -37,6 +38,8 @@ public static function mySQLVersionProvider(): array
         return [
             ['5.7.0', MySQLPlatform::class],
             ['8.0.11', MySQL80Platform::class],
+            ['8.0.13', MySQL8013Platform::class],
+            ['8.0.14', MySQL8013Platform::class],
             ['8.4.0', MySQL84Platform::class],
             ['5.5.40-MariaDB-1~wheezy', MariaDBPlatform::class],
             ['5.5.5-MariaDB-10.2.8+maria~xenial-log', MariaDBPlatform::class],
diff --git a/tests/Functional/Platform/FunctionalIndexTest.php b/tests/Functional/Platform/FunctionalIndexTest.php
new file mode 100644
index 00000000000..c142d8d2905
--- /dev/null
+++ b/tests/Functional/Platform/FunctionalIndexTest.php
@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\DBAL\Tests\Functional\Platform;
+
+use Doctrine\DBAL\Exception\InvalidArgumentException;
+use Doctrine\DBAL\Schema\Table;
+use Doctrine\DBAL\Tests\FunctionalTestCase;
+use Doctrine\DBAL\Tests\TestUtil;
+use Doctrine\DBAL\Types\Types;
+
+use function array_filter;
+use function array_pop;
+
+class FunctionalIndexTest extends FunctionalTestCase
+{
+    public function testGetIndex(): void
+    {
+        $platform = $this->connection->getDatabasePlatform();
+        if (! $platform->supportsFunctionalIndex()) {
+            self::markTestSkipped('Platform does not support functional indexes.');
+        }
+
+        $tableName = 'some_table';
+
+        $table = new Table($tableName);
+        $table->addColumn('column1', Types::INTEGER, ['notnull' => false]);
+        $table->addColumn('column2', Types::INTEGER, ['notnull' => false]);
+        $table->addIndex(['column1', 'column2', '(column2 IS NOT NULL)'], 'func_idx');
+        $this->dropAndCreateTable($table);
+
+        $this->connection->insert($tableName, ['column1' => 1]);
+
+        $tablesFromList = $this->connection->createSchemaManager()->listTables();
+
+        $tables    = array_filter($tablesFromList, static fn (Table $table): bool => $table->getName() === $tableName);
+        $someTable = array_pop($tables);
+
+        self::assertInstanceOf(Table::class, $someTable);
+        self::assertEquals($tableName, $someTable->getName());
+
+        $index = $someTable->getIndex('func_idx');
+
+        self::assertTrue($index->isFunctional());
+
+        if (TestUtil::isDriverOneOf('pdo_pgsql', 'pgsql')) {
+            self::assertEquals(['column1', 'column2', '(column2 IS NOT NULL)'], $index->getColumns());
+        } else {
+            self::assertEquals(['column1', 'column2', '((`column2` is not null))'], $index->getColumns());
+        }
+    }
+
+    public function testPlatformException(): void
+    {
+        $platform = $this->connection->getDatabasePlatform();
+        if ($platform->supportsFunctionalIndex()) {
+            self::markTestSkipped('Skipping, platform supports functional indexes.');
+        }
+
+        $table = new Table('some_table');
+        $table->addColumn('column1', Types::INTEGER, ['notnull' => false]);
+        $table->addColumn('column2', Types::INTEGER, ['notnull' => false]);
+        $table->addIndex(['column1', 'column2', '(column2 IS NOT NULL)'], 'func_idx');
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->dropAndCreateTable($table);
+    }
+}
diff --git a/tests/Functional/Schema/MySQLSchemaManagerTest.php b/tests/Functional/Schema/MySQLSchemaManagerTest.php
index 2b17b6a25be..5502e1af8fc 100644
--- a/tests/Functional/Schema/MySQLSchemaManagerTest.php
+++ b/tests/Functional/Schema/MySQLSchemaManagerTest.php
@@ -6,6 +6,7 @@
 
 use DateTime;
 use Doctrine\DBAL\DriverManager;
+use Doctrine\DBAL\Exception;
 use Doctrine\DBAL\Exception\DatabaseRequired;
 use Doctrine\DBAL\Platforms\AbstractMySQLPlatform;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
@@ -250,6 +251,37 @@ public function testColumnCharsetChange(): void
         );
     }
 
+    public function testCreateTableWithFunctionalIndex(): void
+    {
+        $tableName = 'table_with_functional_index';
+
+        if (! $this->connection->getDatabasePlatform()->supportsFunctionalIndex()) {
+            $this->expectException(Exception::class);
+        }
+
+        $table = new Table($tableName);
+        $table->addColumn('col_string', Types::STRING)
+            ->setLength(100)
+            ->setNotnull(true)
+            ->setPlatformOption('charset', 'utf8');
+
+        $table->addIndex(['(LENGTH(col_string))'], 'length_index');
+
+        $this->dropAndCreateTable($table);
+
+        if (! ($this->connection->getDatabasePlatform()->supportsFunctionalIndex())) {
+            return;
+        }
+
+        $schema = $this->schemaManager->introspectTable($tableName);
+        self::assertArrayHasKey('length_index', $schema->getIndexes());
+        self::assertTrue($schema->getIndexes()['length_index']->isFunctional());
+        self::assertEquals(
+            '(length(`col_string`))',
+            $schema->getIndexes()['length_index']->getColumns()[0],
+        );
+    }
+
     public function testColumnCollation(): void
     {
         $table = new Table('test_collation');
diff --git a/tests/Schema/Platforms/MySQL8013SchemaTest.php b/tests/Schema/Platforms/MySQL8013SchemaTest.php
new file mode 100644
index 00000000000..fe50f64aca6
--- /dev/null
+++ b/tests/Schema/Platforms/MySQL8013SchemaTest.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\DBAL\Tests\Schema\Platforms;
+
+use Doctrine\DBAL\Exception;
+use Doctrine\DBAL\Platforms\MySQL8013Platform;
+use Doctrine\DBAL\Platforms\MySQL80Platform;
+use Doctrine\DBAL\Schema\Table;
+use PHPUnit\Framework\TestCase;
+
+class MySQL8013SchemaTest extends TestCase
+{
+    private MySQL80Platform $platformMysql;
+    private MySQL8013Platform $platformMysql8013;
+
+    protected function setUp(): void
+    {
+        $this->platformMysql8013 = new MySQL8013Platform();
+        $this->platformMysql     = new MySQL80Platform();
+    }
+
+    public function testGenerateFunctionalIndex(): void
+    {
+        $table = new Table('test');
+        $table->addColumn('foo_id', 'integer');
+        $table->addIndex(['foo_id', '(CAST(bar AS CHAR(10)))'], 'idx_foo_id');
+
+        $sqls = [];
+        foreach ($table->getIndexes() as $index) {
+            $sqls[] = $this->platformMysql8013->getCreateIndexSQL(
+                $index,
+                $table->getQuotedName($this->platformMysql8013),
+            );
+        }
+
+        self::assertEquals(
+            ['CREATE INDEX idx_foo_id ON test (foo_id, (CAST(bar AS CHAR(10))))'],
+            $sqls,
+        );
+    }
+
+    public function testGenerateFunctionalIndexWithError(): void
+    {
+        $table = new Table('test');
+        $table->addColumn('foo_id', 'integer');
+        $table->addIndex(['foo_id', '(CAST(bar AS CHAR(10)))'], 'idx_foo_id');
+
+        foreach ($table->getIndexes() as $index) {
+            $this->expectException(Exception::class);
+
+            $this->platformMysql->getCreateIndexSQL(
+                $index,
+                $table->getQuotedName($this->platformMysql),
+            );
+        }
+    }
+}