Join tables query in SQL Server 2012 - tsql

Question

I have two tables like below:
TableA --> categoryId(pk), categoryParentId, catName
TableB --> empId(pk), categoryId, empName, empDesignation
I want to get all catName with respective categoryId from TableA where categoryId=2 of TableB is equal to categoryParentId=2 of TableA. Please help.
Result:
1002 SE
1003 MD

Answer 1

Something like this?
SELECT DISTINCT catName FROM TABLEA WHERE categoryParentId IN (SELECT DISTINCT categoryID from TABLEB);

Answer 2

I hope this query will fulfill your need
SELECT TABLEA.CATNAME AS CATEGORY
from TABLEB INNER JOIN TABLEA
ON TABLEA.CATEGORYPARENTID = TABLEB.CATEGORYID

Answer 3

Solution with INNER JOIN:
select TableA.catName
from TableA
inner join TableB on TableA.categoryParentId = TableB.categoryId
Using INNER JOIN is the recommended way to use for joining tables (as opposed to SELECT ... FROM TableA, TableB ...)
See:
INNER JOIN ON vs WHERE clause
(this question was actually about MySql, but the answers say that it's the same for SQL Server)
Difference in INNER join and cartesian join in SQL Server
Answering your comment (I assume that you wanted the categoryId from TableA):
select TableA.catName, TableA.categoryId
from TableA
inner join TableB on TableA.categoryParentId = TableB.categoryId
where TableB.categoryId = 2

Answer 4

another method...
SELECT
catname
from
tablea a INNER JOIN
tableb b ON
a.categoryParentID = b.categoryID
group by
catname

Answer 5

This should do the trick
SELECT tableA.catName
FROM tableA, tableB
WHERE tableB.categoryId = table1.categoryParentId
AND tableB.categoryId = 2;
If you want the unique catNames, you can use
SELECT distinct tableA.catName
FROM tableA, tableB
WHERE tableB.categoryId = table1.categoryParentId
AND tableB.categoryId = 2;