Displaying whole table after stripping characters in SQL Server - sql

Question

This question has 2 parts.
Part 1
I have a table "Groups":
group_ID person
-----------------------
1 Person 10
2 Person 11
3 Jack
4 Person 12
Note that not all data in the "person" column have the same format.
In SQL Server, I have used the following query to strip the "Person " characters out of the person column:
SELECT
REPLACE([person],'Person ','')
AS [person]
FROM Groups
I did not use UPDATE in the query above as I do not want to alter the data in the table.
The query returned this result:
person
------
10
11
12
However, I would like this result instead:
group_ID person
-------------------
1 10
2 11
3 Jack
4 12
What should be my query to achieve this result?
Part 2
I have another table "Details":
detail_ID group1 group2
-------------------------------
100 1 2
101 3 4
From the intended result in Part 1, where the numbers in the "person" column correspond to those in "group1" and "group2" of table "Details", how do I selectively convert the numbers in "person" to integers and join them with "Details"?
Note that all data under "person" in Part 1 are strings (nvarchar(100)).
Here is the intended query output:
detail_ID group1 group2
-------------------------------
100 10 11
101 Jack 12
Note that I do not wish to permanently alter anything in both tables and the intended output above is just a result of a SELECT query.

Answer 1

I don't think first part will be a problem here. Your query is working fine with your expected result.
Schema:
CREATE TABLE #Groups (group_ID INT, person VARCHAR(50));
INSERT INTO #Groups
SELECT 1,'Person 10'
UNION ALL
SELECT 2,'Person 11'
UNION ALL
SELECT 3,'Jack'
UNION ALL
SELECT 4,'Person 12';
CREATE TABLE #Details(detail_ID INT,group1 INT, group2 INT);
INSERT INTO #Details
SELECT 100, 1, 2
UNION ALL
SELECT 101, 3, 4 ;
Part 1:
For me your query is giving exactly what you are expecting
SELECT group_ID,REPLACE([person],'Person ','') AS person
FROM #Groups
+----------+--------+
| group_ID | person |
+----------+--------+
| 1 | 10 |
| 2 | 11 |
| 3 | Jack |
| 4 | 12 |
+----------+--------+
Part 2:
;WITH CTE AS(
SELECT group_ID
,REPLACE([person],'Person ','') AS person
FROM #Groups
)
SELECT D.detail_ID, G1.person, G2.person
FROM #Details D
INNER JOIN CTE G1 ON D.group1 = G1.group_ID
INNER JOIN CTE G2 ON D.group1 = G2.group_ID
Result:
+-----------+--------+--------+
| detail_ID | person | person |
+-----------+--------+--------+
| 100 | 10 | 10 |
| 101 | Jack | Jack |
+-----------+--------+--------+

Answer 2

Try following query, it should give you the desired output.
;WITH MT AS
(
SELECT
GroupId, REPLACE([person],'Person ','') Person
AS [person]
FROM Groups
)
SELECT Detail_Id , MT1.Person AS group1 , MT2.Person AS AS group2
FROM
Details D
INNER JOIN MT MT1 ON MT1.GroupId = D.group1
INNER JOIN MT MT2 ON MT2.GroupId= D.group2

Answer 3

The first query works
declare #T table (id int primary key, name varchar(10));
insert into #T values
(1, 'Person 10')
, (2, 'Person 11')
, (3, 'Jack')
, (4, 'Person 12');
declare #G table (id int primary key, grp1 int, grp2 int);
insert into #G values
(100, 1, 2)
, (101, 3, 4);
with cte as
( select t.id, t.name, ltrim(rtrim(replace(t.name, 'person', ''))) as sp
from #T t
)
-- select * from cte order by cte.id;
select g.id, c1.sp as grp1, c2.sp as grp2
from #G g
join cte c1
on c1.id = g.grp1
join cte c2
on c2.id = g.grp2
order
by g.id;
id grp1 grp2
----------- ----------- -----------
100 10 11
101 Jack 12