declare @exec_stmt nvarchar(max)
declare @returncode int
declare @comptlevel float(8)
declare @dbid int -- dbid of the database
declare @dbsid varbinary(85) -- id of the owner of the database
declare @orig_cmptlevel tinyint -- original compatibility level
declare @input_cmptlevel tinyint -- compatibility level passed in by user,@cmptlvl80 tinyint -- compatibility to SQL Server Version 8.0,@cmptlvl90 tinyint -- compatibility to SQL Server Version 9.0,@cmptlvl100 tinyint -- compatibility to SQL Server Version 10.0
select @cmptlvl80 = 80,@cmptlvl90 = 90,@cmptlvl100 = 100

-- SP MUST BE CALLED AT ADHOC LEVEL --
if (@@nestlevel > 1)
begin
raiserror(15432,-1,'sys.sp_dbcmptlevel')
return (1)
end

-- If no @dbname given,just list the valid compatibility level values.
if @dbname is null
begin
raiserror (15048,@cmptlvl80,@cmptlvl90,@cmptlvl100)
return (0)
end

-- Verify the database name and get info
select @dbid = dbid,@dbsid = sid,@orig_cmptlevel = cmptlevel
from master.dbo.sysdatabases
where name = @dbname

-- If @dbname not found,say so and list the databases.
if @dbid is null
begin
raiserror(15010,@dbname)
print ' '
select name as 'Available databases:'
from master.dbo.sysdatabases
return (1)
end

-- Now save the input compatibility level and initialize the return clevel
-- to be the current clevel
select @input_cmptlevel = @new_cmptlevel
select @new_cmptlevel = @orig_cmptlevel

-- If no clevel was supplied,display and output current level.
if @input_cmptlevel is null
begin
raiserror(15054,@orig_cmptlevel)
return(0)
end

-- If invalid clevel given,print usage and return error code
-- 'usage: sp_dbcmptlevel [dbname [,compatibilitylevel]]'
if @input_cmptlevel not in (@cmptlvl80,@cmptlvl100)
begin
raiserror(15416,-1)
print ' '
raiserror (15048,@cmptlvl100)
return (1)
end

-- Only the SA or the dbo of @dbname can execute the update part
-- of this procedure sys.so check.
if (not (is_srvrolemember('sysadmin') = 1)) and suser_sid() <> @dbsid
-- ALSO ALLOW db_owner ONLY IF DB REQUESTED IS CURRENT DB
and (@dbid <> db_id() or is_member('db_owner') <> 1)
begin
raiserror(15418,-1)
return (1)
end

-- If we're in a transaction,disallow this since it might make recovery impossible.
set implicit_transactions off
if @@trancount > 0
begin
raiserror(15002,'sys.sp_dbcmptlevel')
return (1)
end

set @exec_stmt = 'ALTER DATABASE ' + quotename(@dbname,'[') + ' SET COMPATIBILITY_LEVEL = ' + cast(@input_cmptlevel as nvarchar(128))

-- Note: database @dbname may not exist anymore
exec(@exec_stmt)

select @new_cmptlevel = @input_cmptlevel

return (0) -- sp_dbcmptlevel
GO

sql;"> sp_dbcmptlevel [ [ @dbname = ] name ] [,[ @new_cmptlevel = ] version ]

sql;"> [ @dbname = ] name