diff --git a/plugins/woocommerce/changelog/fix-33147 b/plugins/woocommerce/changelog/fix-33147
new file mode 100644
index 00000000000..7f81a38c793
--- /dev/null
+++ b/plugins/woocommerce/changelog/fix-33147
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fix
+
+Convert null and '' to 0 before verification to mimic $wpdb->prepare.
diff --git a/plugins/woocommerce/src/Database/Migrations/MetaToCustomTableMigrator.php b/plugins/woocommerce/src/Database/Migrations/MetaToCustomTableMigrator.php
index 0037375f28c..728cdaa70bb 100644
--- a/plugins/woocommerce/src/Database/Migrations/MetaToCustomTableMigrator.php
+++ b/plugins/woocommerce/src/Database/Migrations/MetaToCustomTableMigrator.php
@@ -563,7 +563,7 @@ WHERE
 	private function validate_data( $value, string $type ) {
 		switch ( $type ) {
 			case 'decimal':
-				$value = (float) $value;
+				$value = wc_format_decimal( $value, false, true );
 				break;
 			case 'int':
 				$value = (int) $value;
@@ -778,6 +778,9 @@ WHERE $where_clause
 	 */
 	private function pre_process_row( $row, $schema, $alias, $destination_alias ) {
 		if ( in_array( $schema['type'], array( 'int', 'decimal' ), true ) ) {
+			if ( '' === $row[ $alias ] || null === $row[ $alias ] ) {
+				$row[ $alias ] = 0; // $wpdb->prepare forces empty values to 0.
+			}
 			$row[ $alias ]             = wc_format_decimal( $row[ $alias ], false, true );
 			$row[ $destination_alias ] = wc_format_decimal( $row[ $destination_alias ], false, true );
 		}
diff --git a/plugins/woocommerce/tests/php/src/Database/Migrations/CustomOrderTable/PostsToOrdersMigrationControllerTest.php b/plugins/woocommerce/tests/php/src/Database/Migrations/CustomOrderTable/PostsToOrdersMigrationControllerTest.php
index f4948390a6c..49ac176aebf 100644
--- a/plugins/woocommerce/tests/php/src/Database/Migrations/CustomOrderTable/PostsToOrdersMigrationControllerTest.php
+++ b/plugins/woocommerce/tests/php/src/Database/Migrations/CustomOrderTable/PostsToOrdersMigrationControllerTest.php
@@ -726,4 +726,22 @@ WHERE order_id = {$order_id} AND meta_key = 'non_unique_key_1' AND meta_value in
 
 		return $wpdb_mock;
 	}
+
+	/**
+	 * Test that orders are migrated and verified without errors.
+	 */
+	public function test_verify_migrated_orders() {
+		$order = wc_get_order( OrderHelper::create_complex_wp_post_order() );
+		$this->clear_all_orders();
+
+		// Additional test to assert null values are converted properly.
+		delete_post_meta( $order->get_id(), '_cart_discount_tax' );
+
+		$this->assertEquals( '', get_post_meta( $order->get_id(), '_cart_discount_tax', true ) );
+
+		$this->sut->migrate_order( $order->get_id() );
+		$errors = $this->sut->verify_migrated_orders( array( $order->get_id() ) );
+
+		$this->assertEmpty( $errors );
+	}
 }