在 SQL Select 中将列转换为字符串

Convert column to string in SQL Select

提问by user1188241

I am looking to convert a column to string where the column is a select statment and then concat with another column. This is where my confusion occurs when using CONVERT or CAST.

我希望将一列转换为字符串，其中该列是一个选择语句，然后与另一列连接。这就是我在使用 CONVERT 或 CAST 时发生混淆的地方。

Example:

例子：

 SELECT employeeID
    ,name
    ,location
    ,(SELECT COUNT(DISTINCT loginsFailed)
     FROM users
     WHERE (users.employeedID = userDetails.employeeID)
        AND (users.startdate = 01-01-2013) as LoginCountFailed
  ,(SELECT COUNT(DISTINCT logins)
   FROM users
   WHERE (users.employeedID = userDetails.employeeID)
       AND (users.startdate = 01-01-2013) as LoginCount
 FROM userDetails

Now, this query works perfect in that is provides the correct number of logins and failed as integers. However, I want to use these integer as a string so i can one column. There is a reason why this needs to be one column as string.

现在，这个查询工作完美，因为它提供了正确的登录次数和失败的整数。但是，我想将这些整数用作字符串，以便我可以使用一列。这需要作为字符串的一列是有原因的。

I want to have only 4 columns, not 5. The login column I want to have is loginCountFailed/LoginCount. For example: 3/12. I need it as a string because you cannot divide by a 0 and there are times where the denominator is 0.

我想要只有 4 列，而不是 5。我想要的登录列是 loginCountFailed/LoginCount。例如：3/12。我需要它作为一个字符串，因为你不能除以 0，有时分母是 0。

回答by Serkan Ar?ku?u

For concatanating numbers in MSSQL-2005 you should use CAST

对于 MSSQL-2005 中的连接数字，您应该使用 CAST

CAST(loginsFailed AS VARCHAR(10)) + '/' + CAST(LoginCount AS VARCHAR(10))

loginsFailed and loginCount above is actually your select count distinctfragments

loginsFailed 和 loginCount 上面实际上是你的select count distinct片段

I hope that this works

我希望这有效

CAST ((SELECT COUNT(DISTINCT loginsFailed) FROM users WHERE users.employeedID = userDetails.employeeID AND users.startdate = 01-01-2013) AS VARCHAR(10))
+ '/' +
CAST ((SELECT COUNT(DISTINCT logins) FROM users WHERE users.employeedID = userDetails.employeeID AND users.startdate = 01-01-2013) AS VARCHAR(10))

回答by Woot4Moo

DECLARE @i int
SET @i=98235

--Method 1 : Use CAST function
SELECT CAST(@i as varchar(10))

--Method 2 : Use CONVERT function
SELECT CONVERT(varchar(10),@i)

--Method 3 : Use STR function
SELECT LTRIM(STR(@i,10))

Source

来源

回答by Praveen Nambiar

You can do the following by using CASTor CONVERT:

您可以使用CAST或执行以下操作CONVERT：

CONVERT(VARCHAR(20), YourIntColumn)

OR

或者

CAST(YourIntColumn AS VARCHAR(20))

回答by Kyle Hale

What you wantto do is have a case statement to handle divide by zero logic, not switch to a string for numeric data.

您想要做的是有一个 case 语句来处理除以零逻辑，而不是切换到数字数据的字符串。

SELECT employeeID
    ,name
    ,location
    ,(SELECT CASE WHEN COUNT(DISTINCT logins) = 0 then 0 ELSE
COUNT(DISTINCT loginsFailed) / COUNT(DISTINCT logins)
END
     FROM users
     WHERE (users.employeedID = userDetails.employeeID)
        AND (users.startdate = 01-01-2013) ) as LoginFailRatio
 FROM userDetails

回答by PM 77-1

I think you can just create an outer query here:

我认为你可以在这里创建一个外部查询：

SELECT u.employeeID, u.name, u.location,  
       CONVERT(varchar(10), u.LoginCountFailed) + '/' + CONVERT(varchar(10), u.LoginCount) "Ratio" 
    FROM
        (
         SELECT employeeID
            ,name
            ,location
            ,(SELECT COUNT(DISTINCT loginsFailed)
             FROM users
             WHERE (users.employeedID = userDetails.employeeID)
                AND (users.startdate = 01-01-2013) as LoginCountFailed
          ,(SELECT COUNT(DISTINCT logins)
           FROM users
           WHERE (users.employeedID = userDetails.employeeID)
               AND (users.startdate = 01-01-2013) as LoginCount
         FROM userDetails
        ) u

回答by Ajo Koshy

I think this will do the trick

我认为这会解决问题

Select column1 + '/' + column2 from table1