SQL Cartesian Product

I will explain SQL Cartesian Product in this post.

 

SQL Cartesian Product

 

SQL Cartesian Product is used when any join conditions don’t exist between tables. Cartesian product is created between two data sources, and Optimizer joins every row from one source with every row from the other data source as follows.

 

 

 

 

 

CARTESIAN PRODUCT

  • Cartesian product is mentioned, in case of where the join condition between two tables is not defined.
  • It fetchs all records from the table on the right for each record of the table on the left.

 

For example; hr.regions and hr.locations will be used in the cartesian product as follows.

 

SELECT COUNT(*) FROM hr.regions ;             SELECT COUNT(*) FROM hr.locations ;

                                                                                

 

SELECT * FROM hr.regions, hr.locations;

 

HR.REGIONS has 4 row and HR.LOCATIONS has 23 rows, when you did the cartesian product between these two tables, result will be 4×23 = 92 rows like above.

 

 

 

 

 

 

Do you want to learn Oracle SQL for Beginners, then read the following articles.

Oracle SQL Tutorials For Beginners – Learn Oracle SQL from scratch with Oracle SQL Online Course

 

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About Mehmet Salih Deveci

I am Founder of SysDBASoft IT and IT Tutorial and Certified Expert about Oracle & SQL Server database, Goldengate, Exadata Machine, Oracle Database Appliance administrator with 10+years experience.I have OCA, OCP, OCE RAC Expert Certificates I have worked 100+ Banking, Insurance, Finance, Telco and etc. clients as a Consultant, Insource or Outsource.I have done 200+ Operations in this clients such as Exadata Installation & PoC & Migration & Upgrade, Oracle & SQL Server Database Upgrade, Oracle RAC Installation, SQL Server AlwaysOn Installation, Database Migration, Disaster Recovery, Backup Restore, Performance Tuning, Periodic Healthchecks.I have done 2000+ Table replication with Goldengate or SQL Server Replication tool for DWH Databases in many clients.If you need Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS Consultancy and Training you can send my email adress [email protected].-                                                                                                                                                                                                                                                 -Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS ve linux Danışmanlık ve Eğitim için  [email protected] a mail atabilirsiniz.

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