CREATE TABLE #temp([Source] NVARCHAR(100))
INSERT INTO #temp([Source]) VALUES 
    ('2012-04-27 16:49:24$1$2'),
    ('2012-04-27 17:04:26$2$2'),
    ('2012-04-27 17:18:58$2$2926180')
SELECT [Source],
        PARSENAME(REPLACE([Source],'$','.'),3) AS [日期],
        PARSENAME(REPLACE([Source],'$','.'),2) AS [考勤机号],
        PARSENAME(REPLACE([Source],'$','.'),1) AS [员工编号]
FROM #temp