Q
Problem solve Get help with specific problems with your technologies, process and projects.

# Complex query with DECODE

## I have the following query but it's not working. Can we use nested queries with decode?

I have the following query but it's not working. I want to know where I have gone wrong and please provide me with...

the correct query. Can we use nested queries with decode?

```SELECT A.TYPE,
(SELECT SUM(DECODE(TYPE,'HOT',1,0)) HOT_CAKE,
SUM(DECODE(TYPE,'SWEET',1,0)) SWEET_CAKE
FROM PRODUCT_DETAIL WHERE PRODUCT_CODE = 1 GROUP BY TYPE) A,
(SELECT SUM(DECODE(TYPE,'HOT',1,0)) HOT_BURGER,
SUM(DECODE(TYPE,'SWEET',1,0)) SWEET_BURGER
FROM PRODUCT_DETAIL WHERE PRODUCT_CODE = 2 GROUP BY TYPE) B
WHERE A.TYPE = B.TYPE;
```

I want the output as

```HOT_CAKE   SWEET_CAKE   HOT_BURGER   SWEET_BURGER
50          30         26             45
```

Where you've gone wrong (since you did ask) is to place the derived tables into the SELECT clause instead of the FROM clause.

This is probably what you intended --

```select A.TYPE
, HOT_CAKE
, SWEET_CAKE
, HOT_BURGER
, SWEET_BURGER
from ( SELECT TYPE
, SUM(DECODE(TYPE,'HOT',1,0))
HOT_CAKE
, SUM(DECODE(TYPE,'SWEET',1,0))
SWEET_CAKE
FROM PRODUCT_DETAIL
WHERE PRODUCT_CODE = 1
GROUP BY TYPE ) A
inner
join ( SELECT TYPE
, SUM(DECODE(TYPE,'HOT',1,0))
HOT_BURGER
, SUM(DECODE(TYPE,'SWEET',1,0))
SWEET_BURGER
FROM PRODUCT_DETAIL
WHERE PRODUCT_CODE = 2
GROUP BY TYPE ) B
on A.TYPE
= B.TYPE
```

Here's another way to obtain the same result, which might be a little easier to write --

```select TYPE
, sum(case when PRODUCT_CODE = 1
and TYPE = 'HOT'
then 1 else 0 end
) as HOT_CAKE
, sum(case when PRODUCT_CODE = 1
and TYPE = 'SWEET'
then 1 else 0 end
) as SWEET_CAKE
, sum(case when PRODUCT_CODE = 2
and TYPE = 'HOT'
then 1 else 0 end
) as HOT_BURGER
, sum(case when PRODUCT_CODE = 2
and TYPE = 'SWEET'
then 1 else 0 end
) as SWEET_BURGER
from PRODUCT_DETAIL
group
by TYPE
```

This form of the query also makes it easier to add other products. In addition, it's likely more efficient, since it makes only one pass of the table instead of two passes with a join.

This was last published in April 2006

## Content

Find more PRO+ content and other member only offers, here.

#### Have a question for an expert?

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

#### Start the conversation

Send me notifications when other members comment.

## SearchDataManagement

• ### Connectedness is king, as Neo4j graph database ports to Spark

The Neo4j graph database emphasizes easy relationship mapping for diverse data points. Now, its related Cypher query language is ...

• ### NewSQL databases rise anew -- MemSQL, Spanner among contenders

The NewSQL database was almost hidden when Hadoop and NoSQL arose. Now, as more big data teams move toward production uses, ...

• ### Good data quality for analytics becomes an IT imperative

High-quality data is a must for analytics applications. That's driving more demand for data quality tools, but quality ...

• ### Automating machine learning puts analytical models on autopilot

With data scientists in short supply and the value of machine learning models growing ever more evident, software vendors are ...

• ### Hiring vs. training data scientists: The case for each approach

Hiring data scientists is easier said than done -- so should you try to train current employees in data science skills? That ...

• ### Tableau targets data preparation software with Project Maestro

As Tableau and other high-level applications look to automate more functionality, stand-alone data preparation tools have to ...

## SearchSAP

• ### Responsible sourcing can be good for business

A company's reputation and bottom line can be damaged if its suppliers engage in harmful practices. Responsible sourcing and risk...

• ### SAP TechEd 2017 focuses on next-gen development tools

At SAP TechEd 2017, SAP rolled out some new developer tools that are intended to extend the SAP platform and drive development of...

• ### SAP Analytics Cloud helps paper-maker tell a good business story

SAP Analytics Cloud software is helping paper manufacturer Pratt Industries tell the story of monthly forecasts more accurately, ...

## SearchSQLServer

• ### Microsoft Azure cloud database activity takes off at Connect();

Microsoft Connect(); 2017 saw the addition of MariaDB and Cassandra to the Azure cloud database lineup. Also discussed: A set of ...

• ### Microsoft technology refresh touches SQL Server, integration tooling

Microsoft is at work on a delicate technology refresh affecting database tuning and architecture, as well as data integration and...

• ### Microsoft boosts SQL Server machine learning services

Python and R are among the tools in the SQL Server machine learning toolkit. Native T-SQL scoring is also on the agenda, as ...

## TheServerSide.com

• ### Trying to make DevOps work? Learn how Nike just did it.

Many organizations struggle as they transition to DevOps. But it can be a challenge making DevOps work. Here we look at how Nike ...

• ### Everything to know about overcoming digital transformation challenges

As organizations adopt new technologies, like blockchain, IoT devices and deep learning, strategies must be developed to address ...

• ### How to solve Java and JavaScript performance issues

Given the complexity of client side user interfaces, along with the often limited processing power of many mobile devices, ...

## SearchDataCenter

• ### CA Technologies antes up with AI in mainframe software tools

CA Technologies' debut of mainframe software tools with AI and machine learning extends the platform's relevance in a world ...

• ### Security, vendor choices affect server purchases for IT buyers

Server selection is a quandary for IT, as security, the use of file servers and whether multiple servers of CPU systems will meet...

• ### How to choose a server based on your data center's needs

In an effort to optimize performance in the enterprise, IT should evaluate top priorities to determine how to choose a server and...

## SearchContentManagement

• ### Q&A: New CEO bets on open source future for Acquia CMS

The Acquia CMS took the Red Hat model to content management by commercializing open source Drupal. What's next? We ask co-founder...

• ### CMS analytics arms businesses with a strategic planning edge

Content analytics for CMSes mines business value from free text in data lakes, so it's time to go prospecting for gold with this ...

• ### Enterprise content management systems boost intelligence

Content analytics moves beyond the tried-and-true web analytics style of insights, adding natural language processing and images ...

## SearchFinancialApplications

• ### Finance IT case study: Reporting secrets of Derek Rose

CEO Sacha Rose says specialist reporting tools have saved the company thousands by avoiding unnecessary mistakes.

• ### WestJet turns to gamification to help its Oracle ERP users soar

WestJet's initial gamification project focuses on expense reporting.

• ### The Transformation of HR is Underway

HR is being transformed while we watch.

Close