问题描述
我已经在需要转换为SQL Server的旧报表中遇到这一行。
I have come across this line in an old report that needs converting to SQL Server.
REGEXP_LIKE (examCodes, learner_code)
考试代码是作为模式的源和学习者代码。我知道SQL Server没有REGEXP_LIKE，大多数地方告诉你使用PATINDEX。
examCodes being the source and learner_code being the pattern. I know that SQL Server doesn't have REGEXP_LIKE and most places tell you to use PATINDEX.
这是我认为这将工作：
PATINDEX(learner_code, examCodes)
但是我收到错误：
Msg 4145, Level 15, State 1, Line 54
An expression of non-boolean type specified in a context where a condition is expected, near 'WHERE'.
在MSDN上，语法被指定为
On MSDN the syntax is specified as,
PATINDEX ('%pattern%',expression)
但是learner_code是一个字段，我不能指定一个模式？
But learner_code is a field and I can't specify a pattern?
我没有写这个报告在第一位，所以我很困惑的是什么样的样子无论如何，
I did not write this report in the first place so I'm puzzled to what the pattern it's looking for anyway.
非常感谢
推荐答案
WHERE PATINDEX ('%pattern%',expression) !=0
发现，PATINDEX返回非零值，您需要在WHERE子句中进行比较。
A WHERE 子句必须跟随返回true / false的比较操作。
可能您正在使用PATINDEX而不做比较，这就是为什么错误消息在WHERE子句附近显示非布尔表达式。
If pattern is found , PATINDEX returns non zero value and you need to do a comparison in WHERE clause.A WHERE clause must be followed by comparison operation that returns true / false.
May be you are using PATINDEX without doing the comparison and that is why error message shows non boolean expression near WHERE clause.
使用通配符
WHERE PATINDEX ('%' + CAST(learner_code AS VARCHAR) +'%',examCodes) !=0
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