What is the percentage of orders with 0.2 discount in the Central superstore were purchased by customers who live in Texas?
live in Texas refers to State = 'Texas'; percentage = divide(sum(Order ID) when Discount = 0.2, sum(Order ID)) as percentage
SELECT CAST(SUM(CASE  WHEN T2.Discount = 0.2 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) FROM people AS T1 INNER JOIN central_superstore AS T2 ON T1.`Customer ID` = T2.`Customer ID` WHERE T1.State = 'Texas'