声明：本人对一些版权并不深入了解，但是这个脚本是真的好，帮我解决了问题，特此收藏，并且注明了原文链接，如有侵权，请告知删除。

/*
脚本作用:原来定义为decimal(18,2)类型的所有统一修改为decimal(19,4)。
作者：newsxy
来源：CSDN
原文：https://blog.csdn.net/newsxy/article/details/51280414
版权声明：本文为博主原创文章，转载请附上博文链接！
*/
-- 关闭约束
declare tb cursor for
SELECT sql='alter table ['+d.name+'] NOCHECK CONSTRAINT all'
FROM syscolumns a left join systypes b on a.xtype=b.xusertype
inner join sysobjects d on a.id=d.id and d.xtype='U'and d.name<>'dtproperties'
where b.name in('decimal') GROUP BY d.name
declare @sql1 varchar(1000)
open tb
fetch next from tb into @sql1
while @@fetch_status = 0
begin
print @sql1
exec(@SQL1)
fetch next from tb into @sql1
end
close tb
deallocate tb

-- 修改字段数据类型
declare tb cursor for
SELECT sql='alter table ['+d.name+'] alter column ['+a.name+'] decimal(19,4)'
FROM syscolumns a left join systypes b on a.xtype=b.xusertype
inner join sysobjects d on a.id=d.id and d.xtype='U'and d.name<>'dtproperties'
where b.name in('decimal') order by d.name,a.name
declare @sql2 varchar(1000)
open tb
fetch next from tb into @sql2
while @@fetch_status = 0
begin
print @sql2
exec(@SQL2)
fetch next from tb into @sql2
end
close tb
deallocate tb

-- 恢复约束
declare tb cursor for
SELECT sql='alter table ['+d.name+'] CHECK CONSTRAINT ALL'
FROM syscolumns a left join systypes b on a.xtype=b.xusertype
inner join sysobjects d on a.id=d.id and d.xtype='U'and d.name<>'dtproperties'
where b.name in('decimal') GROUP BY d.name
declare @sql3 varchar(1000)
open tb
fetch next from tb into @sql3
while @@fetch_status = 0
begin
print @sql3
exec(@SQL3)
fetch next from tb into @sql3
end
close tb
deallocate tb
---------------------