SQL Server Books Online上面搜索like,找到了包含%，_,[],[^]几个通配符。
如：select * from mybbs where Content like '[w]%'
like关键字用于搜索匹配某个模式的字符串，或者日期，时间值。
SQL Server Books中的部分解释如下：

Pattern Matching in Search Conditions
The LIKE keyword uses a regular expression to contain the pattern that the values are matched against. The pattern contains the character string to search for, which can contain any combination of four wildcards.

Wildcard Meaning