<p>I'm  trying to create a table with two columns comprising the primary key in MySQL, but I can't figure out the syntax.  I understand single-column PKs, but the syntax isn't the same to create a primary key with two columns.</p>

Example:
```
```
CREATE TABLE `synthesis`.`INV_MasterItemList` (
   `MasterItemList_ID` INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
   `Customer_ID` INTEGER UNSIGNED NOT NULL,
   `Model_ID` INTEGER UNSIGNED NOT NULL,
   `Serial` VARCHAR(45) NOT NULL,
   PRIMARY KEY (`MasterItemList_ID`),
   UNIQUE INDEX `INDEX_UNIQUE`(`Customer_ID`, `Model_ID`, `Serial`)
 )
```
```