SELECT * FROM users WHERE username LIKE '%search_string%'; 在这个查询中,%表示任意字符的出现次数。例如,如果我们搜索的是"abc",那么它将匹配"abcdef"、"abcxyz"、"pqrabcxyz"等等。 另一种方式是使用IN操作符,它允许在WHERE子句中指定多个搜索条件。IN操作符需要一个值列表作为参数,并返回与该列表中的任何...
解析 select substring('123,456',charindex(',','123,456') ,len('123.456')-3) 结果: ',456'意思:截取’123,456‘ 从第4为开始截取 4位substring(字段,第几个字符开始截取,截取长度)charindex(',','123,456') ‘,’的位置 结果为:4len('123.456') 字段长度 结果为:7 ...
其实复杂的情况下,LIKE 'search_string%'也有走索引扫描(Index Scan)的情况,上面情况并不是唯一、绝对的。如下所示 在表Person.Person的 rowguid字段上创建有唯一索引AK_Person_rowguid 那么我们来看看上面所说的这个特殊案例(这里使用一个现成的案例,懒得构造案例了),如何让LIKE %search_string%走索引查找(Index Se...
(substring(nazwisko,1,1), '%') from t_autor where id_autora=26);-- The concat has a trailing % for names that start with the letter. Gives: 另一个例子是: select substring(nazwisko,1,1) from t_autor where id_autora=20; Gives: 然后在子查询中使用: select imie, id_autora from ...
we perform various calculations, analytics, search, replace strings using SQL queries. SQL Server provides many useful functions such as ASCII, CHAR, CHARINDEX, CONCAT, CONCAT_WS, REPLACE, STRING_AGG, UNICODE, UPPER for this purpose. In this article, we explore SUBSTRING, PATINDEX, and CHARINDEX...
Don't use -1 for the position argument -- the substring starts that many characters from the end of the string. You can just do: aux = substr(string, instr(string, '=') + 1) No third argument means "go to the end of the string". Share Improve this answer Follow edited Jun ...
语法1:substr(string A, int start),substring(string A, int start) 返回值:string 说明:返回字符串A从start位置到结尾的字符串 语法2:substr(string A, int start, int len),substring(string A, int start, int len) 返回值:string 说明:返回字符串A从start位置开始,长度为len的字符串 ...
简介: 原文:SQL Server中LIKE %search_string% 走索引查找(Index Seek)浅析 在SQL Server的SQL优化过程中,如果遇到WHERE条件中包含LIKE '%search_string%'是一件非常头痛的事情。原文: SQL Server中LIKE %search_string% 走索引查找(Index Seek)浅析 在SQL Server的SQL优化过程中,如果遇到WHERE条件中包含LIKE '...
Suppose you have a string column in a table that contains phone numbers in the format "(XXX) XXX-XXXX". To extract only the area code, you can use the SUBSTRING function along with thePATINDEXfunction to search for a pattern. In the example below, we look for a pattern that has an ...
The string to search for positional or regular-expression matches. start-position The first character ofsource-stringto return. Ifstart-positionis greater than the length ofsource-string, SUBSTRING returns null. string-length The number of characters fromsource-stringto return. ...