计算多少行具有相同的值

如何编写SQL查询以计算表的num列中特定num值的总数。

例如，选择num = 1

结果：2

+-----+-----+
| NAME | NUM |
+=====+=====+
| SAM  |  1  | 
+-----+-----+
| BOB  |  1  |
+-----+-----+
| JAKE |  2  | 
+-----+-----+  
| JOHN |  4  | 
+-----+-----+

尝试

SELECT NAME, count(*) as NUM FROM tbl GROUP BY NAME

SQL字段

如果要获得以下所有值的结果NUM：

SELECT `NUM`, COUNT(*) AS `count` 
FROM yourTable
GROUP BY `NUM`

或仅针对特定一种：

SELECT `NUM`, COUNT(*) AS `count` 
FROM yourTable
WHERE `NUM`=1

对于特定编号：

SELECT COUNT(1) FROM YOUR_TABLE WHERE NUM = 1

对于所有数字：

SELECT NUM, COUNT(1) FROM YOUR_TABLE GROUP BY NUM

SELECT 
   COUNT(NUM) as 'result' 
FROM 
   Table1 
GROUP BY 
   NUM 
HAVING NUM = 1

试试这个查询

select NUM, count(1) as count 
from tbl 
where num = 1
group by NUM
--having count(1) (You condition)

SQL字段

SELECT sum(num) WHERE num = 1;

SELECT SUM(IF(your_column=3,1,0)) FROM your_table WHERE your_where_contion='something';

例如为您查询：

SELECT SUM(IF(num=1,1,0)) FROM your_table_name;

使用此查询，这将给您输出：

select 
  t.name
  ,( select 
       count (*) as num_value 
     from Table 
      where num =t.num) cnt 
from Table t;