sql server 修改列类型

use bcp;
DECLARE  @dataTypeName nvarchar(102);
--判断是否存在这一列
IF COL_LENGTH(‘B_TaskFileMonitor‘, ‘FileSizeOriginal‘) IS not NULL
    begin
        --查出字段的类型
        select @dataTypeName=t.name from sysobjects o,syscolumns c,systypes t
                where o.id=c.id and c.xtype=t.xtype
                and o.name=‘B_TaskFileMonitor‘ and c.name=‘FileSizeOriginal‘;
        --如果字段不是bigint,那么将其转化为bigint
        if(@dataTypeName<>‘bigint‘) alter table [BCP].[dbo].[B_TaskFileMonitor] alter column [FileSizeOriginal] bigint;
    end