SQL查詢來獲取總行及總行符合特定條件

Question

OK，這裏是我的表看起來像

------------------------------------------------ 
id      type 
----------------------------------------------- 
1      a 
2      b 
3      a 
4      c 
5      c 
7      a 
8      a 
------------------------------------------------ 

現在，我需要一個查詢，可以給我這個輸出...

----------------------------------------------------------------- 
count(*) | count(type=a) | count(type=b) | count(type=c) 
----------------------------------------------------------------- 
8     4     1    3 
------------------------------------------------------------------ 

我只知道使用count（*），以獲得總集，但怎麼做剩餘

Answer 1

SELECT 
COUNT(*), 
COUNT(CASE WHEN type='a' THEN 1 END) as count_a, 
COUNT(CASE WHEN type='b' THEN 1 END) as count_b, 
COUNT(CASE WHEN type='c' THEN 1 END) as count_c, 
FROM table1; 

//or you can do 
SELECT type, COUNT(*) 
FROM table1 
GROUP BY type WITH ROLLUP 

在後一種情況下，您將獲得結果：

a | 4
b | 1
c | 3
null | 8

Answer 2

select count(*),type 
from [TableName] 
Group By Type 

Answer 3

你可以嘗試像

SELECT COUNT(*) Total, 
     SUM(CASE WHEN type='a' THEN 1 ELSE 0 END) as CountOfA, 
     SUM(CASE WHEN type='b' THEN 1 ELSE 0 END) as CountOfB, 
     SUM(CASE WHEN type='c' THEN 1 ELSE 0 END) as CountOfC, 
FROM Table