sql server : count records - sql

Question

I have a tableA (ID int, Match varchar, tot int)
ID Match Tot
1 123
2 123
3 12
4 12
5 4
6 12
7 8
Now, I want to calculate Tot which is total number of match exists in the table. for example 123 occured twice, 12 exist thrice and so on. Also note that I want the count only at first match. here is the expected result.:
ID Match Tot
1 123 2
2 123
3 12 3
4 12
5 4 1
6 12
7 8 1
Another case:
ID Match Count Tot
1 123 2
2 123 1
3 12 10
4 12 10
5 4 3
6 12 5
7 8 7
Now I want to add the count for the same match. expected result:
ID Match Count Tot
1 123 2 3
2 123 1
3 12 10 25
4 12 10
5 4 3 3
6 12 5
7 8 7 7
Thanks

Answer 1

WITH tableA(ID, Match) AS
(
SELECT 1,123 UNION ALL
SELECT 2,123 UNION ALL
SELECT 3,12 UNION ALL
SELECT 4,12 UNION ALL
SELECT 5,4 UNION ALL
SELECT 6,12 UNION ALL
SELECT 7,8
)
SELECT *,
CASE
WHEN ROW_NUMBER() OVER (PARTITION BY Match ORDER BY ID) = 1
THEN COUNT(*) OVER (PARTITION BY Match)
END AS Tot
FROM tableA
ORDER BY ID

Answer 2

SELECT match, COUNT(match ) as Tot
FROM tableA
GROUP BY match

Answer 3

Solution 1:
DECLARE #MyTable TABLE
(
ID INT PRIMARY KEY
,Match VARCHAR(10) NOT NULL
,Tot INT NULL
);
INSERT #MyTable(ID, Match)
SELECT 1, 123
UNION ALL
SELECT 2, 123
UNION ALL
SELECT 3, 12
UNION ALL
SELECT 4, 12
UNION ALL
SELECT 5, 4
UNION ALL
SELECT 6, 12
UNION ALL
SELECT 7, 8;
--SELECT
SELECT *
,CASE
WHEN ROW_NUMBER()OVER(PARTITION BY a.Match ORDER BY a.ID ASC)=1
THEN COUNT(*)OVER(PARTITION BY a.Match)
END TotCalculated
FROM #MyTable a;
--UPDATE
WITH MyCTE
AS
(
SELECT a.Tot
,CASE
WHEN ROW_NUMBER()OVER(PARTITION BY a.Match ORDER BY a.ID ASC)=1
THEN COUNT(*)OVER(PARTITION BY a.Match)
END TotCalculated
FROM #MyTable a
)
UPDATE MyCTE
SET Tot = TotCalculated;
SELECT *
FROM #MyTable;
Solution 2:
UPDATE #MyTable
SET Tot = NULL;
SELECT x.ID, y.Num
FROM
(
SELECT b.Match, MIN(b.ID) ID
FROM #MyTable b
GROUP BY b.Match
) x INNER JOIN
(
SELECT a.Match, COUNT(*) AS Num
FROM #MyTable a
GROUP BY a.Match
) y ON x.Match = y.Match
ORDER BY x.ID
UPDATE #MyTable
SET Tot = t.Num
FROM #MyTable z
INNER JOIN
(
SELECT x.ID, y.Num
FROM
(
SELECT b.Match, MIN(b.ID) ID
FROM #MyTable b
GROUP BY b.Match
) x INNER JOIN
(
SELECT a.Match, COUNT(*) AS Num
FROM #MyTable a
GROUP BY a.Match
) y ON x.Match = y.Match
) t ON z.ID = t.ID;
SELECT *
FROM #MyTable;