Solved

MySQL SQL Syntax question multiple table query

Posted on 2008-06-18
5
221 Views
Last Modified: 2013-12-12
I have two tables 'Residential' and 'property_coordinates' that feature both feature a sMLSNumber field and the Residential table has a sSubdivision field.  I am trying to select all data where the sSubdivision equals Pines in table Residential and the sMLSNumber matches in both tables.  What am I doing wrong?  Can someone edit my syntax to work properly?
SELECT * FROM Residential, property_coordinates
	WHERE sSubdivision='Pines'
	AND sMLSNumber=sMLSNumber"

Open in new window

0
Comment
Question by:pda4me
  • 3
5 Comments
 

Author Comment

by:pda4me
ID: 21812295
I fixed a typo " and am now getting this error FYI, how do I work around:

#1052 - Column 'sMLSNumber' in where clause is ambiguous
0
 
LVL 10

Accepted Solution

by:
Nellios earned 400 total points
ID: 21812373
The problem lies in the fact that mysql server doesn't know to which tables column you are refering by sMLSNumber since it exists in both tables that participate in the query:

You can try one of the snipets bellow.


/*1st Approach*/
SELECT * FROM Residential, property_coordinates
        WHERE sSubdivision='Pines'
        AND Residential.sMLSNumber=property_coordinates.sMLSNumber
 
/*2nd Approach*/
select * from Residential
inner join property_coordinates on property_coordinates.sMLSNumber=Residential.sMLSNumber

Open in new window

0
 

Author Comment

by:pda4me
ID: 21812562
Is there a performance increase in one versus the other?
0
 
LVL 20

Assisted Solution

by:virmaior
virmaior earned 100 total points
ID: 21812879
the two queries will probably evaluate the same since MySQL optimizes the query that you send it.  So properly speaking these are not approaches to the query so much as approaches to programming practices.

I personally always prefer the second syntax.  With the first syntax, it isn't clear whether the parts of the WHERE clause are clarifying which rows you want to retrieve (e.g. sSubdivision = 'Pines' ) and which parts are explaining how the data is related ( Residential.sMLSNumber=property_coordinates.sMLSNumber ).  In the second syntax, it is obvious, explicit, and required.
0
 

Author Closing Comment

by:pda4me
ID: 31468311
Thanks!
0

Featured Post

3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Creating and Managing Databases with phpMyAdmin in cPanel.
These days socially coordinated efforts have turned into a critical requirement for enterprises.
The viewer will learn how to create and use a small PHP class to apply a watermark to an image. This video shows the viewer the setup for the PHP watermark as well as important coding language. Continue to Part 2 to learn the core code used in creat…
This tutorial will teach you the core code needed to finalize the addition of a watermark to your image. The viewer will use a small PHP class to learn and create a watermark.

772 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question