what is the difference between UNION AND UNIONALL

Answer Posted / krishna kant kumar

The UNION operator returns all rows from two or multiple tables and eliminates any duplicate rows but the UNION ALL operator returns from both queries, including all duplications.
The UNION operator can use DISTINCT keyword but the UNION ALL cannot it.

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

How to connect to oracle using service name instead of sid?

553


How to create lov dynamically at runtime & attach to text field?

664


How to load excel data sheet to oracle database

588


What is a trace file and how is it created in oracle?

554


What to do if the binary spfile is wrong for the default instance?

563






Why use resource manager in Oracle?

665


What is the difference between Delete, Truncate and Drop in Oracle?

606


I am using an Oracle 8i Database my data contains Clob data. I am using toad version 7.6 i am able to get the data in toad but unable to extract the data in excel.when trying to extract the data into the excel the toad error says out of memory. Can any body please help me to extract the data through the same toad version. Thanks in advance

1847


What is the data pump export utility?

645


Explain what are the advantages of views?

613


What is a Garbage Collection? and what is full recursive Garbage collection?

2389


In AP we done Customizations for Late Payments Charges. For Reporting Purpose What are the Documents Prepared for Customer Understanding??

1210


What is Java Pool in Oracle?

604


List out the components of logical database structure of oracle database.

585


Why do you use stored procedures and state some of its disadvantages?

564