学步园

    DECLARE @USERROWS NVARCHAR(MAX)
SET @USERROWS=''
SET @USERROWS='wode'
print LEN(@USERROWS)
SET @USERROWS=SUBSTRING(@USERROWS,0,LEN(@USERROWS))
print @USERROWS     --结果为 wod
    
DECLARE @USERROWS NVARCHAR(MAX)
SET @USERROWS='wode'
SET @USERROWS=SUBSTRING(@USERROWS,1,LEN(@USERROWS)-1)
print @USERROWS     --结果为 wod