how to use multiple where clause?

Question

Here is my code, I had to split it in three different codes, how can I combine these three into one, all come from same table.

code #1

select SUM(`Line_Total`) as Total,
    SUM(`_Revenue`) as Incr
     from `table 1`
     where `Month`='201909'

code #2

select SUM(`Channel`) as SKG
    from `table 1`
 where `Division`='Good'  and `Month`='201909'

code #3

select SUM(`Channel`) as Direct
  from `table 1`
  where `Division`='BAD' and `Month`='201909'

Please tell me how I can optimize the code and combine into 1 code only. as they all are in same table, but I dont know how to use multiple where clause with 3 sums

Answer 1

Queries 2 and 3 read a subset of the rows already read by query 1 so you can easily combine them by using that as a base and moving the additional filters into CASE expressions.

SELECT SUM(`Line_Total`) AS Total,
       SUM(`_Revenue`)   AS Incr,
       SUM(CASE WHEN `Division` = 'Good' THEN `Channel` END) AS SKG,
       SUM(CASE WHEN `Division` = 'BAD' THEN `Channel` END) AS Direct
FROM   `TABLE 1`
WHERE  `Month` = '201909'