Database Interview questions (SQL Server)

root

　　how many right answer you could provide ?

• What is Normalization? What does 3rd normal form state? (Could be 1st, 2nd etc)
  
• Where would you use a De-normalized database?
  
• What is the difference between a Truncate and a Delete statement?
  
• What is the use of a Temp table?
  
• What is the scope of a Temp table? Can we access a temp table of one stored procedure from another stored procedure?
  
• What are triggers? When does a trigger get executed? Example of usage.
  
• What are the difference types of Joins available?
  
• What is the difference between a Left Outer join and Right Outer Join?
  
• What are correlated sub queries? What is good or bad about them?
  
• What is the difference between a group by and having clause?
  
• What is an Index? Why is it used? Types of Index? What is good or bad about them?
  
• Write a query – There will be some question to test SQL concepts like outer joins, group by, sub queries etc
  
• What is the difference between a stored procedure and a function? Advantages?
  
• What is a surrogate key? (Sometimes called System key)
  
• How can you give access to the data of a table or tables without giving access to tables? (Concept of Views)
  
• What is the quickest way to import data from a file to a table without writing programs? (DTS Import/Export wizard, DTS packages).
  
• diff between delete and truncate
  
• when you will use having clause
  
•  what is index,adv and dis adv
  
• what is trigger
  
• what is temp table,how many types are there,when you will use?
  
• what is cursor?when you will use?
  
• when you will use group by
  
• there is a scenario like 2 or 3 tables and we need to join those and we need to retrieve data.
  
• Here different types of questions they will ask
  

          1) what is the difference between sub query and join
          2) how many types of joins are there?
          3) if we are using 1 join then they will ask why you are this one,why can't other join
          4) can you tell me in how many different ways you can solve this  scenario
5) more questions we will get here on joins on various different scenarios
26. they will ask questions on few string functions(like what is mid,replace etc)
27. what is compiling and parsing?
28. what is normalization?what is 1st,2nd,3rd normalforms?
29. what is primary key,foreign key,unique key?diff between them?
30. can primary key contain nulls?
31. types if integrity constraints?
32. most of the times they will give scenarios and we need to tell the query(they will give time)  and those will be on joins or using group by or using temp table.
           

• Difference between Stuff and replace
  
• what is the use of NO LOCK keyword using in the query
  
• Can we roll back the data if we use delete statement?
  
• difference between stored procedure and function
  
• what is referential integrity
  
• how will you get number of rows in a table
  
• Scenario question: Table A and Table B has empid. How will you get empid that are not in table b
  
• what is sub query
  
• difference between local temp table and global temp table
  
• What is view? Can you insert or update in a view?
  
• Why we are going for stored procedure?
  
• difference between local temp table and global temp table
  
• Types of indexes.
  
• What is view? Can you insert or update in a view?
  
• Why we are going for stored procedure?
  
• What is difference between Surrogate and Natural Key?
  
• When can we implement Self and Outer Joins?
  
• Use of @@RowCount.
  
• Syntax and writing queries for different types of join.
  
• What is composite Key?
  
• Who transactions are maintained in SQL?
  
• Explain Joins, Their Types with example?
  
• What is stored procedure? Why we use stored procedure?
  
• what is referential integrity
  
• Stored procedure Vs UDF.
  
• Explain View?
  
• What is Association Table?
  
• What are the relationships exist between two tables?