How to do boolean field based on a condition

Question

0.00/5 (No votes)

See more:

I have this table

Id  ParentId
1     0
2     0
3     0
4     3
5     3
6     2

i want to create a stored procedure that retrieves Ids based on the input of the parent and it also should retrieve a new field that returns true or false if the Id has other Ids that consider it as a parent. What i mean is

if the input to my stored procedure is 0 then the result should be:

Id ParentId hasId
1    0      0 it's false cause there is no Id in table considers Id 1 as a parent
2    0      1  it's true because Id =6 considers  Id 2 as a parent
3    0      1  it's true because Id =4 and 5 considers Id 3 as a parent

What I have tried:

CREATEPROCEDURE [dbo].[GetIds]
	@ParentId int

  AS

  SELECT 
		Table.Id 
	       ,Table.ParentId

  FROM		Table

WHERE	 Table.ParentId = @ParentId 

RETURN 0

How to do the hasId logic?

Posted 2-May-20 7:59am

Member 14800672

Updated 2-May-20 10:22am

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

MadMyche · Accepted Answer · 2020-05-02T10:23:00

Solution 1

What you need to do is to JOIN the table back onto itself.

Play around with this sample

SQL

DECLARE @Table TABLE (ID INT, ParentID INT)
INSERT @Table VALUES (1, 0), (2, 0), (3, 0), (4, 3), (5, 3), (6, 2)

DECLARE @ParentID INT = 0

SELECT    p.ID, p.ParentID, Matches = case count(c.ID) when 0 then 0 else 1 end
FROM      @Table P
FULL JOIN @Table c on p.id = c.parentID
WHERE     p.ParentID = @ParentID
GROUP BY  p.ID, p.ParentID

Posted 2-May-20 10:23am

MadMyche

Comments

Member 14800672 2-May-20 16:41pm

Thank you so much, i tried left join instead of full join and it worked as well. Which is better and did you use full join for a reason?

MadMyche 2-May-20 18:25pm

Left Join would work as well; the Full was leftover from an earlier version of this

Maciej Los 4-May-20 15:34pm

5ed!

MadMyche 4-May-20 18:13pm

Thank You