What is the difference between UNION and UNIONALL?

Answer Posted / suresh

UNION statement effectively does a SELECT DISTINCT on the
results set. If you know that all the records returned are
unique from your union, use UNION ALL instead, it gives
faster results.

Is This Answer Correct ?    13 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What are entities and relationships?

739


What is a data collection table?

723


What is not null constraint?

814


Explain the types of indexes.

836


How to connect php with different port numbers?

721






i have made a project i vb.net n created a .exe of it after installing it in to any pc, the database (sql express) is not geting accesed i.e the aplication cuts the link of the database, so plz help in this matter.

1575


What is indexing in sql server with example?

697


How do I clean up sql server transaction log?

742


Explain query editor regions

796


What is difference between unique and primary key?

650


How to how to convert numeric expression data types using the convert() function??

722


What is data source object?

719


how would you improve etl (extract, transform, load) throughput?

761


What is report server project?

122


Disadvantages of the indexes?

752