Question

我有一个包含nvarchar（max）列的表。我想搜索此列以查看是否已生成特定语句。我可以通过以下方式做到这一点：

SELECT sectionText
FROM Section
WHERE sectionText LIKE '%This statement is true%'

但是，这会返回整个部分文本。我希望它只返回前一个字符前50个字符和50个字符。

Answer 1

你可以试试这些：

--This line would replace your phrase
SELECT REPLACE(sectionText,'This statement is true','')
FROM Section ;

--Another way...
--Assuming your column is: 50 characters + ' ' + 'This statement is true' + ' ' + The other 50 characters
SELECT  SUBSTRING(sectionText, 1, 50) + ' ' + SUBSTRING(sectionText, 74, 50)
FROM Section 
WHERE sectionText LIKE '%This statement is true%';

您可以查看此MSDN链接以获取更多info。让我提供一些简单的例子：

SELECT x = SUBSTRING('abcdef', 2, 3)

SELECT x= SUBSTRING('abcdef', 2,1)  + SUBSTRING('abcdef', 5,1)

感谢@SeanLange评论（一种更好的方法）：

DECLARE @sectionText VARCHAR(1200) = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut a dui quam. Sed pretium purus sed lorem volutpat fringilla. Sed imperdiet sodales justo, sed suscipit mi maximus ac. Aenean ligula quam, gravida a eleifend a, vulputate nec dolor. Donec sit amet mi in justo mollis mollis eu ac magna. Integer dolor nulla, mollis eu tempus et, lobortis in libero. Etiam vitae pulvinar mauris. Curabitur a nulla orci. This statement is true. Nam non est nec urna aliquam gravida. Sed diam lorem, finibus eu arcu et, iaculis ullamcorper diam. Sed vitae tellus odio. In hac habitasse platea dictumst. Maecenas lobortis consequat erat. Fusce aliquam imperdiet.';
DECLARE @MyPattern varchar(10) = 'This statement is true'; 

DECLARE @firstPosition INT, @lastPosition INT, @gambit INT, @textLenght INT;

--Grabbing the positions
SET @firstPosition = CHARINDEX(@sectionText, @sectionText,49)
SET @gambit = LEN(@MyPattern)
SET @lastPosition = @firstPosition + (@gambit + 1); --Sum 1 because of a White Space of a 
SET @textLenght = LEN(@sectionText);

SELECT  SUBSTRING(@sectionText, 1, @firstPosition) + ' ' + SUBSTRING(@sectionText, @lastPosition, @textLenght) AS [CleanText]
--FROM Section 
--WHERE sectionText LIKE '%This statement is true%';

Answer 2

这是我能够做到的：

SELECT SUBSTRING(sectionText, CHARINDEX('This statement is true', sectionText)-50, 100)
FROM Section
WHERE sectionText LIKE '%This statement is true%'

选择nvarchar max的子字符串

2 个答案: