An index represents a schema object that contains an entry for each value that appears in the indexed column(s) of the table or cluster and provides direct, … Read More
A database is an organized collection of data.
A table in SQL is a set of data which is systematically displayed in rows and columns.… Read More
|Clustered indexes||Non-clustered indexes|
|One table can have only one clustered index.||One table can have multiple non-clustered index.|
|Clustered indexes can be read rapidly.||Clustered indexes|
A subquery refers to a select statement that is embedded in a clause of another select statement.
SELECT columnName1, columnName2 FROM tableName1, tableName2 WHERE columnName OPERATOR… Read More
The nvl() function return an alternative value when an expression is NULL.
string : represents the string to test for a null value.… Read More
SQL stands for Structured Query Language. SQL is a computer language for accessing databases. It is used to store, manipulate and retrieve the data stored in … Read More