What is the difference between join and union.

Answer Posted / sompalli krishna

Join: joins are used to combine the columns from one or
more tables(join using one table is possible for self
join).output should B more than one column.
It is constraint based.Columns r joined based on similar
column names and datatypes also on both the tables.

union: union is used to combine the columns from one or
more tables.Output should B one column.
It is not constraint based.Any no. of columns can be
combined without using any condition.But the data types
should be same immaterial to column names.
Contact me for any queries on 09885790989

Is This Answer Correct ?    0 Yes 5 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

How many triggers can be applied on a table?

508


What plvcmt and plvrb does in pl/sql?

874


Write a sql select query that only returns each name only once from a table?

565


What is rank function in sql?

530


What is data modelling in sql?

519






Which column of the user triggers data dictionary view displays the database event that will fire the trigger?

595


explain primary keys and auto increment fields in mysql : sql dba

518


what are the differences between procedure-oriented languages and object-oriented languages? : Sql dba

502


what is the use of set statement in tsql? : Transact sql

532


List different type of expressions with the example.

546


What are local and global Indexes and where they are useful.

925


what is normalization? : Sql dba

559


Is not null in sql?

558


what is log shipping? : Sql dba

607


Is sql injection illegal?

595