判断两个图片是否相同

--自定义函数：

if object_id('tablename') is not null drop table tablename

create table tablename

(id int identity(1, 1),

a1 image,

a2 image)

go

insert into tablename(a1, a2) select 'aaa', 'aaa'

insert into tablename(a1, a2) select 'bbb', 'bba'

insert into tablename(a1, a2) select 'ccc', 'ccc'

insert into tablename(a1, a2) select 'ddd', 'ddc'

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if object_id('Compare_Image') is not null drop function Compare_Image

go

create function Compare_Image(@a1 image, @a2 image) returns int

as

begin

declare @n int, @i int, @j int

declare @b1 varbinary(8000), @b2 varbinary(8000)

set @n = 1

if datalength(@a1) <> datalength(@a2) --长度不同

set @n = 0

else

begin

set @i = 0

set @j = (datalength(@a1) - 1) / 8000 + 1

while @i <= @j

begin

set @b1 = substring(@a1, @i * 8000 + 1, case @i when @j then datalength(@a1) % 8000 else 8000 end)

set @b2 = substring(@a2, @i * 8000 + 1, case @i when @j then datalength(@a2) % 8000 else 8000 end)

if @b1 <> @b2

begin

set @n = 0

break

end

set @i = @i + 1

end

end

return(@n)

end

go

select * from tablename where dbo.Compare_Image(a1, a2) = 1

/*

id a1 a2

1 0x616161 0x616161

3 0x636363 0x636363

*/

drop function Compare_Image

--------------------------------------------------------------------------------

drop table tablename