MySQL汇总两行之一中包含值的所有行

Question

I have a table that may have the search value in one of two columns, column B and/or column C. I want to produce a summary based on column A, showing how many times the selected search value (eg. x) appears in either column for each person. I want to count the totals in both columns.

+--------+------+----+
|  name  | B    | C  |
+--------+------+----+ 
| john   | x    | z  |
| john   | x    | x  |
| john   | y    | x  |
| peter  | x    | z  |
| peter  | x    | z  |
| amanda | x    | x  |
| amanda | x    | x  |
| amanda | x    | x  |
| amanda | x    | y  |
| amanda | x    | y  |
+--------+-----------+

In the above example, assuming my search value is x, I want to count how many times x appears for each person in column B and/or column C. I also want to produce grand totals, and produce this output:

Name   B  C

john   2  2
peter  2  0
amanda 5  3
total  9  5

I can do it for each column separately like this:

     SELECT name, COUNT(*) as count FROM table 
          WHERE A = 'x'
          GROUP BY name
          ORDER BY count DESC";

     SELECT name, COUNT(*) as count FROM table 
          WHERE B = 'x'
          GROUP BY name
          ORDER BY count DESC";

I can then loop around doing separate fetches on the output from each and combine them, but I want to know if there is a way to do the check and counting in one mysql statement for the two columns please?

Answer 1

If you want the sum of each column separately then you could use the following ( SQL Fiddle ):

(
  SELECT MTA.Name, Sum(MTA.B = 'x') AS BSum, Sum(MTA.C = 'x') AS CSum
  FROM MyTable MTA
  GROUP BY MTA.Name
)
UNION
(
  SELECT 'Total' AS name, Sum(MTB.B = 'x') AS BSum, Sum(MTB.C = 'x') AS CSum
  FROM MyTable AS MTB
)

Or if you want the sum of both columns combined then you could do something like the following ( SQL Fiddle ):

(
  SELECT MTA.Name, Sum(MTA.B = 'x') + Sum(MTA.C = 'x') AS PersonTotal
  FROM MyTable MTA
  GROUP BY MTA.Name
)
UNION
(
  SELECT 'Total' AS name, Sum(MTB.B = 'x') + Sum(MTB.C = 'x') AS PersonTotal
  FROM MyTable AS MTB
)

Answer 2

select...
case count (when A = 'x' then A else null) end,
case count (when B = 'x' then B else null) end
...

EDIT: Oop, left out the count...

Answer 3

SELECT name, 
COUNT(CASE WHEN B='x' THEN 1 ELSE 0 END) as B,
COUNT(CASE WHEN C='x' THEN 1 ELSE 0 END) as C FROM table 
GROUP BY name;

Answer 4

SELECT name, sum(if(B='x',1,0)) as c1, sum(if(C='x',1,0)) as c2FROM table 
WHERE A = 'x'
GROUP BY name
ORDER BY c1 desc, c2 desc

Answer 5

MySQL Shortcut,

SELECT Name,
       SUM(B='x') TotalX,
       SUM(C='x') TotalY
FROM   TableName
GROUP  BY Name