improve performance in looker derived table

[yanwu1205-16427]

I have a question about how to improve query performance in looker. I use derived table in looker to transform data. In the sql code for derived table, I use cte, a lot of case statement and join etc. but the query performance is not good. Since I use bigquery as data warehouse and connected to looker, will it improve the performance if I transform data in bigquery and then load into looker? In addition, how to improve the query performance when it has lots of case statements in sql code for the derived table? Will PDT helpful？