However most of the time we'll only deal with simple queries such as select where and join. More complex example is just group by and simple aggregation such as

However most of the time we'll only deal with simple queries such as select where and join. More complex example is just group by and simple aggregation such as max min count. People struggling with sql because they usually don't know easier way to query that they resulting to use more complex query. For example `select where id in` and `case when` are both powerful query that many don't know or under utilized. With `select where in` for example, we can do object mapping / join on application level instead db level.