如何计算mssql中具有特定数据的行数

I have the following table:

我有下表：

Items:

项目：

ID     Type     StockExists  
01     Cellphone   T
02     Cellphone   F
03     Apparrel    T

I want to count the number of items with existing stocks, i.e., the number of rows with StockExists='T'. I was performing the query as;

我想计算现有股票的项目数，即StockExists ='T'的行数。我正在执行查询;

Select count(StockExists) 
From [Items] where StockExists='T'

but it is always returning 1. What is the right way to do it?

但它总是回归1.做正确的方法是什么？

Edit:

编辑：

Also, how to perform another such Count operation and add them together in one row, for example,

另外，如何执行另一个这样的Count操作并将它们放在一行中，例如，

Select count(StockExists) 
From [Items] where StockExists='T'` and `Select count(Type) 
From [Items] where Type='Cellphone'` ? 

2 个解决方案

#1

SELECT 
    COUNT(*) As ExistCount 
FROM 
    dbo.Items
WHERE
    StockExists='T'

So your query should work.

所以你的查询应该有效。

Result:

结果：

EXISTCOUNT
    2

Demo

演示

Update

更新

How to perform another such Count operation and add them together in one row, for example, Select count(StockExists) From [Items] where StockExists='T' and Select count(Type) From [Items] where Type='Cellphone' ?

如何执行另一个这样的Count操作并将它们一起添加到一行，例如，选择计数（StockExists）来自[Items]其中StockExists ='T'和Select count（Type）来自[Items]其中Type ='Cellphone'？

You can use SUM with CASE:

您可以将SUM与CASE一起使用：

SELECT 
  ExistCount = SUM(CASE WHEN StockExists='T' THEN 1 ELSE 0 END) ,
  CellphoneCount = SUM(CASE WHEN Type='Cellphone' THEN 1 ELSE 0 END) 
FROM 
    dbo.Items

Result:

结果：

EXISTCOUNT    CELLPHONECOUNT
    2               2

Demo

演示

#2

Select Sum(Case when field = 'this' then 1 else 0 end) as Total from YourTable

从YourTable中选择Sum（Field ='this'然后1，0结束时为Case）