Please indicate store id in the state of California that have been applied 20% discount in store.
"California" is the name of State; in store refers to Sales Channel = 'In-Store'; 20% discount refers to Discount Applied = '0.2'
SELECT T FROM ( SELECT DISTINCT CASE  WHEN T2.State = 'California' AND T1.`Sales Channel` = 'In-Store' AND T1.`Discount Applied` = 0.2 THEN T2.StoreID END AS T FROM `Sales Orders` T1 INNER JOIN `Store Locations` T2 ON T2.StoreID = T1._StoreID ) WHERE T IS NOT NULL