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

# Analytic solution to counting rows in runs

## Reader Paul Moore has supplied an analytic solution to the problem posed in a previous answer, "Counting rows in runs."

Reader Paul Moore of Atos Origin S.A. was kind enough to respond with an analytic solution to the problem posed in a previous answer, Counting rows in runs. His solution follows.

Assume a table called runs, defined as follows:

```create table runs
( id number
, category varchar2(1)
);
insert into runs values (1, 'X');
insert into runs values (2, 'X');
insert into runs values (3, 'X');
insert into runs values (4, 'Y');
insert into runs values (5, 'Y');
insert into runs values (6, 'X');
insert into runs values (7, 'X');
commit;```

The following works:

```select block, category, count(*)
from (
select
id,
category,
sum(prev_cat) over
(order by id
rows unbounded preceding) block
from (
select
id,
category,
case when (category = lag(category)
over (order by id) )
then 0
else 1
end
prev_cat
from
runs
)
)
group by block, category
order by block

BLOCK   C  COUNT(*)
-----   -  --------
1   X         3
2   Y         2
3   X         2```

The trick is to work out from the inner inline view. First, use "lag" to identify when the category changes. You can use decode to get an Oracle 8i solution -- I used the 9i case operator. You also need to watch out for the first row, where lag() returns null. Then, sum the number of category changes which occur "before" a given row - that is its "block" (ie, the sequence number of the run it's in). Then you just count and group by the block number.

Hope this is of interest.

Yes, it is. Thanks very much, Paul.

#### 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

• ### Weighing the use of third-party database administration tools

Database expert Chris Foot details the key reasons why DBAs should consider using third-party database administration to fill ...

• ### InfluxDB Cloud 2.0 expands open source time series database

While the core open source InfluxDB 2.0 project is still in alpha, InfluxData has advanced its cloud service to support new ...

• ### New cloud and on-premises options for Oracle Autonomous Database

Oracle introduced new cloud and on-premises deployment options for its namesake database as the tech vendor’s Oracle OpenWorld ...

• ### SAP BI platform stays strong due to cloud-based architecture

A cloud-native BI platform along with domain-specific applications that can be embedded to serve the needs of various industries ...

• ### Tableau 2019.3 highlighted by enhanced AI, new data catalog

Tableau released its third-quarter update Wednesday, featuring Explain Data, an enhanced augmented intelligence tool, and Tableau...

• ### Oracle BI platform on the comeback trail

Time had seemingly left Oracle's business intelligence tools behind -- until the vendor responded by consolidating its BI ...

## SearchSAP

• ### Navy sails SAP ERP systems to AWS GovCloud

The Navy consolidated 26 various ERP systems onto SAP HANA on the AWS GovCloud, leading to data reduction, lower TCO, and setting...

• ### SAP HANA application collects concussion data for real-time analysis

Protecht, an SAP HANA based system, enables teams in contact sports to measure and analyze data about hits though an IoT sensor ...

• ### S/4HANA public cloud vs. private cloud: Compare the pros, cons

In addition to SAP's on-premises and hybrid models, the vendor offers S/4HANA in public and private clouds. Here's a look at the ...

## SearchSQLServer

• ### SQL Server database design best practices and tips for DBAs

Good database design is a must to meet processing needs in SQL Server systems. In a webinar, consultant Koen Verbeeck offered ...

• ### SQL Server in Azure database choices and what they offer users

SQL Server databases can be moved to the Azure cloud in several different ways. Here's what you'll get from each of the options ...

• ### Using a LEFT OUTER JOIN vs. RIGHT OUTER JOIN in SQL

In this book excerpt, you'll learn LEFT OUTER JOIN vs. RIGHT OUTER JOIN techniques and find various examples for creating SQL ...

## TheServerSide.com

• ### Eclipse launches Che 7 IDE for Kubernetes development

The Eclipse Foundation has introduced Eclipse Che 7, a new version of the Eclipse Che cloud-based integrated development ...

• ### Java's popularity hinges on future developers, adaptability

Java needs to focus on the youth, adapt to emerging tech and constantly evaluate its performance to remain popular among ...

• ### Cloud marketplace as a service creates new dev possibilities

A neutral cloud marketplace would allow developers to pick and choose applications, without the constraints of one cloud. What ...

## SearchDataCenter

• ### New Dell EPYC servers embrace AMD Rome chips

Dell EMC goes from Naples to Rome with a new line of EPYC servers, including Ready Solutions for high-performance computing and ...

• ### Can next-gen SIEM help cybersecurity initiatives?

More organizations are using SIEM, AI and cloud technology to minimize security breaches. Though despite interest, this ...

• ### IBM z15 mainframe secures data across multi-cloud environments

IBM unveiled the latest in its line of mainframes capable of processing 1 trillion web transactions a day. The IBM z15 ...

## SearchContentManagement

• ### Nintex launches no-code workflow automation tool

Nintex has launched a no-code workflow automation tool, Workflow Generator, in an effort to bridge the gap between IT departments...

• ### Cohesion is latest Acquia acquisition

While Acquia would not provide specifics of the deal, the decision behind the acquisition of Cohesion was the chance to bring ...

• ### 3 things to learn before considering blockchain integration

Paul Swider, CTO at RealActivity LLC, discusses how to use blockchain technology to increase the security and usefulness of ...

## SearchHRSoftware

• ### SuccessFactors customers to see big Qualtrics impact

SuccessFactors is rethinking its HCM suite as it works to integrate Qualtrics into its applications. But HR managers are ...

• ### HiQ Labs vs LinkedIn case OKs robot monitoring of employees

A U.S. Court of Appeals ruled on the LinkedIn vs HiQ lawsuit, which could help shape how services gather information on social ...

• ### MyPayrollHR collapse stirs allegations, questions, anger

The problems created by the closing of MyPayrollHR may take a long time to resolve. The FBI has been contacted and lawsuits are ...

Close