How to split data in SQL Server table row - sql

Question

I have table of transaction which contains a column transactionId that has values like |H000021|B1|.
I need to make a join with table Category which has a column CategoryID with values like H000021.
I cannot apply join unless data is same.
So I want to split or remove the unnecessary data contained in TransctionId so that I can join both tables.
Kindly help me with the solutions.

Answer 1

Create a computed column with the code only.
Initial scenario:
create table Transactions
(
transactionId varchar(12) primary key,
whatever varchar(100)
)
create table Category
(
transactionId varchar(7) primary key,
name varchar(100)
)
insert into Transactions
select'|H000021|B1|', 'Anything'
insert into Category
select 'H000021', 'A category'
Add computed column:
alter table Transactions add transactionId_code as substring(transactionid, 2, 7) persisted
Join using the new computed column:
select *
from Transactions t
inner join Category c on t.transactionId_code = c.transactionId
Get a straighforward query plan:

Answer 2

You should fix your data so the columns are the same. But sometimes we are stuck with other people's bad design decisions. In particular, the transaction data should contain a column for the category -- even if the category is part of the id.
In any case:
select . . .
from transaction t join
category c
on transactionid like '|' + categoryid + |%';
Or if the category id is always 7 characters:
select . . .
from transaction t join
category c
on categoryid = substring(transactionid, 2, 7)

Answer 3

You can do this using query :
CREATE TABLE #MyTable
(PrimaryKey int PRIMARY KEY,
KeyTransacFull varchar(50)
);
GO
CREATE TABLE #MyTransaction
(PrimaryKey int PRIMARY KEY,
KeyTransac varchar(50)
);
GO
INSERT INTO #MyTable
SELECT 1, '|H000021|B1|'
INSERT INTO #MyTable
SELECT 2, '|H000021|B1|'
INSERT INTO #MyTransaction
SELECT 1, 'H000021'
SELECT * FROM #MyTable
SELECT * FROM #MyTransaction
SELECT *
FROM #MyTable
JOIN #MyTransaction ON KeyTransacFull LIKE '|'+KeyTransac+'|%'
DROP TABLE #MyTable
DROP TABLE #MyTransaction