diff --git a/tests/WP_SQLite_Query_Tests.php b/tests/WP_SQLite_Query_Tests.php
index 059fed9..119f1f2 100644
--- a/tests/WP_SQLite_Query_Tests.php
+++ b/tests/WP_SQLite_Query_Tests.php
@@ -505,6 +505,21 @@ public function testRecoverSerialized() {
 		$this->assertEquals( $obj, $unserialized );
 	}
 
+	public function testOnDuplicateKey() {
+		$this->assertQuery(
+			'CREATE TABLE `test` (
+				`id` INT PRIMARY KEY,
+				`text` VARCHAR(255),
+			);'
+		);
+		// The order is deliberate to test that the query works with the keys in any order.
+		$this->assertQuery(
+			'INSERT INTO test (`text`, `id`)
+			VALUES ("test", 1)
+			ON DUPLICATE KEY UPDATE `text` = "test1"'
+		);
+	}
+
 	public function testShowColumns() {
 
 		$query = 'SHOW COLUMNS FROM wp_posts';
diff --git a/wp-includes/sqlite/class-wp-sqlite-translator.php b/wp-includes/sqlite/class-wp-sqlite-translator.php
index 542ee6c..0558842 100644
--- a/wp-includes/sqlite/class-wp-sqlite-translator.php
+++ b/wp-includes/sqlite/class-wp-sqlite-translator.php
@@ -2803,9 +2803,10 @@ private function translate_on_duplicate_key( $table_name ) {
 		$this->rewriter->add( new WP_SQLite_Token( '(', WP_SQLite_Token::TYPE_OPERATOR ) );
 
 		$max = count( $conflict_columns );
-		foreach ( $conflict_columns as $i => $conflict_column ) {
+		$i   = 0;
+		foreach ( $conflict_columns as $conflict_column ) {
 			$this->rewriter->add( new WP_SQLite_Token( '"' . $conflict_column . '"', WP_SQLite_Token::TYPE_KEYWORD, WP_SQLite_Token::FLAG_KEYWORD_KEY ) );
-			if ( $i !== $max - 1 ) {
+			if ( ++$i < $max ) {
 				$this->rewriter->add( new WP_SQLite_Token( ',', WP_SQLite_Token::TYPE_OPERATOR ) );
 				$this->rewriter->add( new WP_SQLite_Token( ' ', WP_SQLite_Token::TYPE_WHITESPACE ) );
 			}