Mysql calculate multiple SUM() varialbe

Question

I want to calculate 2 sum() i have tried query as below it works but very slowly. Any ideas to make it better?

SELECT customer, 
       SUM(CASE WHEN book_day BETWEEN '2020-01-01' AND '2020-01-31'  
                THEN pax+free 
                ELSE 0 
                END) AS January,
       SUM(CASE WHEN book_day BETWEEN '2020-02-01' AND '2020-02-31'  
                THEN pax+free 
                ELSE 0 
                END) AS February,
       ( SUM(CASE WHEN book_day BETWEEN '2020-01-01' AND '2020-01-31'  
                  THEN pax+free 
                  ELSE 0 
                  END) + 
         SUM(CASE WHEN book_day BETWEEN '2020-02-01' AND '2020-02-31'  
                  THEN pax+free 
                  ELSE 0 
                  END) ) AS total
 FROM rezervations  

How can i make simplier like January + February as total

Answer 1

keep BETWEEN '2020-01-01' AND '2020-02-29' in where clause.

make sure there is index on book_day column

SELECT customer, 
SUM(CASE WHEN book_day BETWEEN '2020-01-01' AND '2020-01-31' THEN pax+free ELSE 0 END) as January,
SUM(CASE WHEN book_day BETWEEN '2020-02-01' AND '2020-02-29'  THEN pax+free ELSE 0 END) as February,
(SUM(CASE WHEN book_day BETWEEN '2020-01-01' AND '2020-02-29'  THEN pax+free ELSE 0 END) ) as total
 FROM rezervations 
WHERE
book_day BETWEEN '2020-01-01' AND '2020-02-29'