在sqlite中计算一个列中的多项？ [英] Count muttiple items in the sqlite a column ?

问题描述

例如：

 id columnA 
 
  1  black 
  2  red 
  3  red 
  4 绿色
  5  red 
  6  black 
  7 白色

我想要计算黑色和红色项目的总数。结果应为5。



此代码工作正常，但如果我尝试添加红色则无效。

< pre lang =java> long count = DatabaseUtils.longForQuery（db， SELECT COUNT（*）FROM mytable WHERE columnA =' + black + '，null）;

对不起，我的英文不好，谢谢你的帮助...



我尝试了什么：



long count = DatabaseUtils.longForQuery（db，SELECT COUNT（*）FROM mytable WHERE columnA =（'+black+'AND'+ red+），null）;

解决方案

SELECT somecolumn，someothercolumn，COUNT（*）

FROM my_table

GROUP BY somecolumn，someothercolumn





SQLite：count函数 [ ^ ]

  select   type ，count（ type ）来自 表 组 按 型; 

For example :

id   columnA

1    black
2    red
3    red
4    green
5    red
6    black
7    white 

I want to count total of "black" and "red" items. Result should be "5".

This code work fine, but if I try to add "red" it's not working.

long count = DatabaseUtils.longForQuery(db, "SELECT COUNT(*) FROM mytable WHERE columnA = '" + "black" + "', null);

Sorry my bad English, thanks for helping...

What I have tried:

long count = DatabaseUtils.longForQuery(db, "SELECT COUNT(*) FROM mytable WHERE columnA = ('" + "black" + "' AND '" + "red" + "'"), null);

解决方案

SELECT somecolumn,someothercolumn, COUNT(*)
FROM my_table
GROUP BY somecolumn,someothercolumn


SQLite: count Function[^]

select type, count(type) from table group by type;

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