t-sql 正则表达式(1/2)

t-sql 正则表达式
创建程序集 clrregexclass.cs，
并使用 c:windowsmicrosoft.netframeworkv2.0.50727csc.exe /target:library clrregexclass.cs 编译为 clrregexclass.dll 文件。
using system;
using system.data;
using system.data.sqlclient;
using system.data.sqltypes;
using microsoft.sqlserver.server;
using system.text.regularexpressions;

public partial class regexp
{
// 验证字符串中是否包含与指定的匹配模式一致的字符串
    [sqlfunction(isdeterministic = true, isprecise = true)]
    public static sqlboolean regexismatch(sqlstring expression, sqlstring pattern)
    {
        return new sqlboolean(regex.ismatch(expression.tostring(), pattern.tostring()));
    }

// 替换字符串中与指定的匹配模式一致的字符串
    [sqlfunction(isdeterministic = true, isprecise = true)]
    public static sqlstring regexreplace(sqlstring expression, sqlstring pattern, sqlstring replacement)
    {
        return new sqlstring(regex.replace(expression.tostring(), pattern.tostring(), replacement.tostring()));
    }

// 提取字符串中与指定的匹配模式一致的字符串
    [sqlfunction(isdeterministic = true, isprecise = true)]
    public static sqlstring regexsubstring(sqlstring expression, sqlstring pattern, sqlint32 position, sqlint32 occurrence)
    {
        if (expression.tostring().length < position) return new sqlstring("");
        if (position <= 0) position = 1;
        if (occurrence <= 0) occurrence = 1;

        match m = regex.match(expression.tostring().substring((int) position - 1),pattern.tostring());
        for (int i = 1; i < (int)occurrence; i++)
        {
            m = m.nextmatch();
            if (!m.success) return new sqlstring("");
        }

        return new sqlstring(m.tostring());
    } 1 2