MySQL Count distinct values from one column

Question

I have a table having three columns:

I want the count of those values which have C equal to 2 but with distinct values of B

So in this case for C = 2, count = 2 (B=2 and B=1)

I used the following command:

Select count(*) from mytable where C=2 group by (B)

but it yields:

count(*)
3

I have tried using "distinct" but it can't be use to select from one column

Adrien Brunelat · Accepted Answer · 2017-08-22 12:33:39Z

2

Have you tried

SELECT COUNT(DISTINCT B) FROM mytable WHERE C = 2;

answered Aug 22, 2017 at 10:16

Adrien Brunelat

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Comments

Lamar · Accepted Answer · 2017-08-22 10:17:14Z

1

Use sub query like this:

Select count(*) from (
    select distinct B where c=2
)

answered Aug 22, 2017 at 10:17

Lamar

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