计算mysql中的列项

Question

I have a column called "WasCancelled" in a MySQL DB, it's of a Boolean type.

I save the number 0,1 and 2 to it.

I need a query that will count how many one's, two's and zeros are there.

for example: my column:

WasCanceled
-----------
    0
    0
    1
    1
    1
    2
    0
    0   
    0
    2
    0
    0
    1

I need the query to output:

 number | times
 -------|------
  "0"   |   7
  "1"   |   4
  "2"   |   2

please help.

thank you.

Dave.

Answer 1

You can do this by grouping:

SELECT WasCancelled, COUNT(*)
FROM <Table>
GROUP BY WasCancelled

If you need more information, look here for details on Group By and Count .

Update

To include the question in the comments: to restrict on special values, you can add a WHERE clause:

SELECT WasCancelled, COUNT(*)
FROM <Table>
WHERE WasCancelled = "1"
GROUP BY WasCancelled

In further questions, please edit your overall question to include sub-questions or open new topics. Please read How To Ask Good Questions .

Update 2

SQL also allows the HAVING clause, which is like WHERE but allows the comparison of aggregated values. See here for details (eg you want to know which value appears more than 5 times, etc.).

Answer 2

Use GROUP BY with COUNT fuction:

Try this:

SELECT WasCanceled, COUNT(1) as times 
FROM tableA 
GROUP BY WasCanceled;

Answer 3

I think this might work!

select
  count(WasCanceled) as CNT, WasCancelled
from
  YourTableNameHere
group by
  WasCanceled

Answer 4

这适合我

SELECT WasCanceled AS number, COUNT(WasCanceled) AS times FROM tblTest GROUP BY WasCanceled