要用多少次select count(*)？

[bjseaman]

统计符合某一条件的记录总数
select count(*) from table where city='北京'
select count(*) from table where city='上海'

如果城市有100个，我要统计每个城市的记录数量，
难道要select count(*) 100次？
1000个呐？1000次？

有点晕了...

[cqfeng]

select city,count(*) from tableName
group by city

[pp4u]

SELECT *,(SELECT COUNT(*) FROM table WHERE city = J.city) AS count FROM table J

[sear]

同意cqfeng() 的说法 进行分组统计

[colee]

Select city,Count(*) From tableName Group By city Having city='***'

[colee]

sorry,上面回复取消

[cloudchen]

SELECT
SUM(CASE city WHERE '北京' THEN 1 ELSE 0 END),
SUM(CASE city WHERE '上海' THEN 1 ELSE 0 END)
FROM table

[cloudchen]

上面错了
SELECT
SUM(CASE city WHEN '北京' THEN 1 ELSE 0 END),
SUM(CASE city WHEN '上海' THEN 1 ELSE 0 END)
FROM table