使用PHP检查sql查询列是否包含某些数据

I'm working with an external database in Wordpress and trying to use an IF statement if a column has a certain value. So the column 'period' will have the value of either 'week', 'month' or 'year'. I want to be able to change the data based on that. Am I headed in the right direction? Any help appreciated.I'm working with an external database in Wordpr