SQL 如何在Sql Server中检查字符串长度然后选择子字符串
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How to check string length and then select substring in Sql Server
提问by Code Rider
In a view, i have a column commentswhich may contain large string. I just want to select first 60 characters and append the '...' at the end of the selected string.
在一个视图中，我有一个可能包含大字符串的列注释。我只想选择前 60 个字符并在所选字符串的末尾附加 ' ...'。
For selecting first 60 characters i have used following query:
为了选择前 60 个字符，我使用了以下查询：
select LEFT(comments, 60) as comments from myview
Now i want its processing as below:
现在我想要它的处理如下：
- Check it contains more then 60 characters or not.
- If contains then select only first 6o characters and append three dots at the end.
- If it doesn't contain more then 60 characters then select whole string without appending three dots at the end.
- 检查它是否包含超过 60 个字符。
- 如果包含则仅选择前 6o 个字符并在末尾附加三个点。
- 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。
Thanks
谢谢
回答by John Woo
To conditionally check the length of the string, use CASE.
要有条件地检查字符串的长度，请使用CASE.
SELECT CASE WHEN LEN(comments) <= 60
THEN comments
ELSE LEFT(comments, 60) + '...'
END As Comments
FROM myView
