Solved

Add IF THEN clause in SELECT statement

Posted on 2008-06-17
2
815 Views
Last Modified: 2008-08-20
Using MySQL 5 and Coldfusion8. I have fields for "price" and "price_status" among other fields. Price_status has 2 options, set and notset.  The user will enter a price and select if that price is set or not.  

My select query looks like this...

SELECT SUM(amount) as amount, ROUND(AVG(weight)) as avg_weight,  ROUND(AVG(price),2) as avg_price
FROM deal_master LEFT JOIN (deal_lots LEFT JOIN sale_lots ON deal_lots.lot_id = sale_lots.origin_lot_id) ON deal_lots.deal_master_id = deal_master.deal_master_id
WHERE sale_lots.delivery_taken_date IS NULL

1 of my inventory units includes fields for amount, weight and price.  In this query, I want to include the amount and weight from all of my products but I only want to average the prices that are set.  I can't add a where clause like WHERE price_type = set since that would then exclude all of my weight and amounts.  Is there anyway I could tell it to use weights and amounts on all inventory, but only use prices where price_type = set?  
0
Comment
Question by:MFredin
2 Comments
 
LVL 142

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 21804857
you are looking for the CASE WHEN <condition> THEN <value> ... END  syntax structure:
http://dev.mysql.com/doc/refman/5.0/en/case-statement.html
0
 
LVL 20

Accepted Solution

by:
virmaior earned 500 total points
ID: 21812933
in order to get this to work, you have to make an additional change in addition to the IF clause.  You can use your current query and only include the data that matter as below (but then you must manually do the AVERAGE).

Or you can rearrange your query into two subqueries one of which includes all of the data and the other of which contains only the data with set prices.  In the latter case, you can use the AVG function but then you are querying the data twice anyway.
SELECT SUM(amount) as amount, 
ROUND(AVG(weight)) as avg_weight,  
ROUND(
        SUM(
              IF(price_status = 'set',price,0)
        ) / COUNT(IF(price_status = 'set',price,1)),2) as avg_price
FROM deal_master LEFT JOIN (deal_lots LEFT JOIN sale_lots ON deal_lots.lot_id = sale_lots.origin_lot_id) ON deal_lots.deal_master_id = deal_master.deal_master_id
WHERE sale_lots.delivery_taken_date IS NULL

Open in new window

0

Featured Post

Efficient way to get backups off site to Azure

This user guide provides instructions on how to deploy and configure both a StoneFly Scale Out NAS Enterprise Cloud Drive virtual machine and Veeam Cloud Connect in the Microsoft Azure Cloud.

Question has a verified solution.

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

Suggested Solutions

PROBLEM: How to add your own buttons to the bottom toolbar with paging info ( result count ). While creating a cfgrid, I ran into an issue where I wanted to embed my own custom buttons where the default ones ( insert / delete / etc… ) are for aes…
Introduction Since I wrote the original article about Handling Date and Time in PHP and MySQL (http://www.experts-exchange.com/articles/201/Handling-Date-and-Time-in-PHP-and-MySQL.html) several years ago, it seemed like now was a good time to updat…
Windows 10 is mostly good. However the one thing that annoys me is how many clicks you have to do to dial a VPN connection. You have to go to settings from the start menu, (2 clicks), Network and Internet (1 click), Click VPN (another click) then fi…
This video shows how to use Hyena, from SystemTools Software, to bulk import 100 user accounts from an external text file. View in 1080p for best video quality.

806 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