how many type of subquery?
Answers were Sorted based on User's Feedback
Answer / rajkumar
As database developer, you must have ever written
subqueries in either SQL Server or any other database
platform. This article will describe shortly about types of
subquery.
A subquery is inner query that will be used by outer query.
A subquery could return scalar value or a series of value.
Based on query dependency, a subquery could be self-
contained or correlated one. A self-contained subquery is a
subquery independent from outer query, and correlated
subquery is a subquery that is referencing to a row in
outer query.
Self-contained subquery is easier to debug than correlated
subquery. And it is executed only once whereas correlated
subquery is executed once for each row of outer query.
Sample of self-contained subquery that returns scalar value
is shown below :
Select customerid
From dbo.orders
Where employeeid = (select employeeid from dbo.employees
where lastname = ‘RAJ’);
This query returns customers list whose employee is RAJ.
| Is This Answer Correct ? | 9 Yes | 1 No |
What are the different types of normalization?
What are examples of triggers?
What is the full meaning of dml?
What is catalog views?
How to provide values to stored procedure parameters in ms sql server?
What methods do you follow to protect from sql injection attack?
What are the differences between char and varchar in ms sql server?
What is measure group, measure? : sql server analysis services, ssas
What is ms sql server service broker?
Is foreign key a primary key?
What is read uncmmited?
as a general practice, it is recommended to have dbo be the owner of all database objects however, in your database you find number of tables owned by a user other than dbo, how could you fix this? : Sql server administration
Oracle (3259)
SQL Server (4518)
MS Access (429)
MySQL (1402)
Postgre (483)
Sybase (267)
DB Architecture (141)
DB Administration (291)
DB Development (113)
SQL PLSQL (3330)
MongoDB (502)
IBM Informix (50)
Neo4j (82)
InfluxDB (0)
Apache CouchDB (44)
Firebird (5)
Database Management (1411)
Databases AllOther (288)