如何在Sql Server中检查字符串长度然后选择子字符串 [英] How to check string length and then select substring in Sql Server

问题描述

在视图中，我有一列 comments 可能包含大字符串.我只想选择前 60 个字符并在所选字符串的末尾附加...".

In a view, i have a column comments which may contain large string. I just want to select first 60 characters and append the '...' at the end of the selected string.

为了选择前 60 个字符，我使用了以下查询:

For selecting first 60 characters i have used following query:

select LEFT(comments, 60) as comments from myview

现在我希望它的处理如下:

Now i want its processing as below:

1. 检查它是否包含超过 60 个字符.
2. 如果包含，则仅选择前 6o 个字符并在末尾附加三个点.
3. 如果它不包含超过 60 个字符，则选择整个字符串而不在末尾附加三个点.

谢谢

推荐答案

要有条件地检查字符串的长度，请使用 CASE.

To conditionally check the length of the string, use CASE.

SELECT  CASE WHEN LEN(comments) <= 60 
             THEN comments
             ELSE LEFT(comments, 60) + '...'
        END  As Comments
FROM    myView

• SQLFiddle 演示

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