CODEWITHSUNDEEP
mysqlcountsubquery
r.yaz
r.yaz

Reputation: 23

MYSQL get count percentage by group

Hello i have a Database that looks like that 

------------------
| Tag   |  Value |
------------------
| A     | Passed |
| A     | Failed |
| B     | Failed |
| A     | Failed |
| B     | Failed |
------------------

I am trying to write a query to get the percentage of passed per type

output example:

A: 33%
B: 50%

so far i tried multiple queries but the closest result i had was:

SELECT Tag, ((SELECT COUNT(*) FROM TABLE WHERE value= 'Passed') / Count(*)) * 100 AS 'Percentage to all Passed' FROM Table WHERE Value= 'Passed' GROUP BY Tag;

but the result i got where not correct

Any help on this ?

Upvotes: 1

Views: 29

Answers (2)

forpas
forpas

Reputation: 164099

You can do it with the aggregate function AVG():

SELECT Tag, 
  100.0 * AVG(value = 'Passed') AS `Percentage to all Passed` 
FROM Table 
GROUP BY Tag;

Upvotes: 1

ScaisEdge
ScaisEdge

Reputation: 133370

You could use a cross join 

SELECT Tag
       , count(*)/t.tot
FROM my_table m  

cross  join  (
    select count(*) tot
    from my_table 
) t
where m.value  ='passed'

Upvotes: 1

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