What are different types of joins and whats the difference between them ?

INNER JOIN
Inner join shows matches only when they exist in both tables.Example in the below SQL
there are two tables Customers and Orders and the inner join in made on Customers

What is normalization? What are different type of normalization?

It is set of rules that has been established to aid in the design of tables that are meant to
be connected through relationships. This set of rules is known as Normalization.

how to get second max salary in sql

select min(sal) as sal from emp where sal   in 
(select distinct top 2 sal from emp with (nolock) order by sal desc ) 


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how to get the column names and corresponding datatypes in particular table using SQL Server

SELECT column_name 'Column Name',

data_type 'Data Type',

character_maximum_length 'Maximum Length'

FROM information_schema.columns

SQL Union Operator | SQL Union ALL Operator | Difference between Union and Union ALL Operators in SQL |

Union Operators are used to combine the result of two or more select queries into single result set.

SQL UNION Operator:

SQL Union Operator is used to combine the result of two or more select statement queries into single result set. The Union Operator is used to select only distinct values from two tables.

what is stored procedure in Sql server | what are the advantages of using stored procedures in sql server

A stored procedure is a group of sql statements that has been created and stored in the database. Stored procedure will accept input parameters so that a single procedure can be used over the network by several clients using different input data. Stored procedure will reduce network traffic and increase the performance. If we modify stored procedure all the clients will get the updated stored procedure