SQL Interview Questions

Select emp_id,emp_name,salary from employee a, (Select salary,dense_Rank() over (order by salary DESC) rank_sal from employee)b where a.salary=b.salary and rank_sal=7; The Inline Query will orde...

select salary data only

Yes we can use DML operations on single table view.

For perfomance optimization.
Like in case of datawarehousing operation the no of tables to be joined to get the desired output might be too high. In such a case we de-normalize to serve our purpose.

sp_RENAME old_table_name, new_table_name

SQL >> rename table_name1 to new_table_name;

dbms does not support client/server architecture and rdbms supports client/server architecture.

Eg for DBMS is FoxPro,IMS... For RDBMS is SQL,ORACLE...

Few steps for query tuning. 1) Check for if any sub query or exists or not exists is there if yes then try to change it in the joins 2) Try to check the way joins had been written try to put it in f...

Following a Tuning Methodology Objectives:: • Determine performance problems • Manage performance • Describe tuning methodologies • Identify goals for tuning • Describe automatic SQL tunin...

The subquery scan the complete table to apply so its slow whether joins are much faster.

Joins are performance killer

Yes, using SQL UPPER function.

Code
SELECT UPPER(name) FROM TABLE;

True

In SQL 2005 only != and <> operator perform same operation

^= does not work

now SQL SERVER 2008 onwards we can have 1 cluster index and 999 non cluster index on one table.

clustered index  - the index order matches the order of physically stored data.cluster index can be used on table that doent get changes frequentlyusing DML statement on cluster index column have...

Only SELECT statement can be used in Functions. INSERT,UPDATE,DELETE are used.

syntax verification done from client only not in the server only valid sequel statements are send to the server if syntax is not correct client throws error

It will fetch all the data from employee table..then u give a select * command..

sql is a language
sql server is a RDBMS relational database management system.

Sql Server is a (RDBMS) Relation Database Management System where as SQL is Structure Query Language.

"sql declare @temp_numeric table (value nvarchar(500)) declare @i int=1,@len int,@ans nvarchar(100)=,@str nvarchar(100) DECLARE @count INT SELECT VALUE INTO #temp FROM dbo.numer...

Code
SELECT REPLACE(TRANSLATE(LOWER(99sAmn44423mz44),abcdefghijklmnopqrstuvwxyz, ), ,) FROM dual 

Select Max(Salary) from Emp Where Salary < (Select Max(Salary) from Emp)

select max(salary) from EmpTable where salary not in (select max(salary) from EmpTable));

How write a SQL statement to query the result set and display row as columns and columns as row?

The simplest way to implement this in SQL 2000/OracleSelect * from table1Create a temp table with No of columns = No of rows in table 1No of rows = No of columns in table 1and insert the data into the temp table using a loop logic.

Varchar & Varchar2 both having the same size, & working as same.
Bt the main diff is varchar is an ANSI Datatype & Varchar2 is the Oracle datatype.

Varchar - If we declare datatype as varchar then it will occupy space for null values. It can store upto 2000 bytes of character.

Varchar2 - If we declare datatype as varchar2, it will not occupy any space. It can store 4000 bytes of character.

Thanx,

select AUTHOR_NAME,BOOK_NAME from books101
where AUTHOR_NAME in
(select author_name from books101 group by author_name having count(*)>1);

select book_name,author_name,count(*) from books
group by book_name,author_name
having count(*)>1