Iterate through result-sets in T-SQL - tsql

Question

I would like to write a stored procedure using a statement to iterate through a result-set of records provided by another statement, and union the end results into one single result-set. Can anyone advise on an approach for this?
For example, a generic set of records to iterate through:
SELECT sys.schemas.name + '.' + sys.objects.name as [schm_obj]
FROM sys.objects
INNER JOIN sys.schemas
ON sys.objects.schema_id = sys.schemas.schema_id
AND sys.schemas.name IN ('dbo')
Generic query to be executed on each record:
SELECT DISTINCT referenced_schema_name + '.' + referenced_entity_name
FROM sys.dm_sql_referenced_entities(#schm_obj,'OBJECT')
The parameter #schm_obj to be replaced by a single field value returned in each row of the first query; eventually, I would like to union all results. Any advice would be greatly appreciated.

Answer 1

You need to do dyanmic sql to do this. I am confused as you are stating a procedure then showing a table function. Table Functions unless something changed in 2012 cannot do dynamic sql. If you want to basically create a programmable object you can use to get data that YOU SUPPLY the schema or meta detail to get to it I would use a dynamic procedure that would label what you got and then give you the value of it. Then you could insert this into a table variable and iterate or insert into it till your heart's content.
create proc dbo.Dynaminizer
(
#ObjName nvarchar(64)
)
as
BEGIN
declare #SQL nvarchar(1024)
Select #SQL = 'Select ''' + #ObjName + ''' as Name, ' + #ObjName + ' from sys.tables'
EXECUTE sp_executesql #SQL
END
declare #temp table ( name varchar(32), value varchar(128))
insert into #Temp
exec Dynaminizer 'name'
insert into #Temp
exec Dynaminizer 'object_id'
select *
from #Temp
UPDATE LATER THAT DAY....
If you just want to take values from one table or set and then perform operations in a function that takes a schema and a name combo then there is another method to do that. I would use a cte to make a custom column and then do a cross apply to perform that dataset in a function for how many rows that are in the set. This will evaluate your function like it was executing it for each value and then posting the results. There is no need to union unless you are more specific for what you are wanting to do. You can take it even further and if you want the dependencies inline(as opposed to seperate rows) you can relate the dataset back to itself and then do an xml type to cast out the dependencies into a comma seperated list.
Example usage of both:
-- multi row example to show referencing relationships
with procs as
(
Select
schema_name(schema_id) + '.' + name as Name
from sys.procedures p
)
select
p.Name
, referenced_schema_name + '.' + referenced_entity_name as Ref
from procs p
cross apply sys.dm_sql_referenced_entities(p.Name,'OBJECT')
;
-- take it a step further and put relationships inside a single column
with procs as
(
Select
schema_name(schema_id) + '.' + name as Name
from sys.procedures p
)
, setup as
(
select
p.Name
, referenced_schema_name + '.' + referenced_entity_name as Ref
from procs p
cross apply sys.dm_sql_referenced_entities(p.Name,'OBJECT')
)
Select distinct
Name
, stuff(
(
select
', ' + Ref
from setup x
where x.Name = m.Name
for xml path('')
)
, 1, 2, '') as Dependencies
from setup m