sql

In this article, we will see about deadlocks in SQL and how to trace and detect a deadlock with SQL Server Profiler. Let’s start with an introduction to Deadlock. What is Deadlock? Deadlock in SQL server is a scenario where two or more resources are trying to access the same resource which is mutually being … Read more

In this article, I will explain a scenario where the user has to remove duplicate records with different statuses. Scenario Consider below the table with 2 columns (Employee Name and Status) Now, write a query to fetch a unique Employee Name like this – If the Employee Name is unique then select it and if … Read more

Very frequent question asked in interview is Differences between Stored Procedure and Functions.Below are the differences between these 2. 1) Functions must return a value. Stored procedure need not be.2) Stored procedures can be called using EXEC command where as Functions can be called from another SQL Statement.3) Stored Procedures are precompiled. Functions are not precompiled.4) Generally Stored procedures are … Read more

Important SQL Query asked in InterviewSQL query to check a record in table, if exist then insert else update the record. BEGIN  IF EXISTS (SELECT * FROM [users] WHERE email=@email)    UPDATE [users] SET updated_date = GETDATE() WHERE email=@emailELSE    INSERT INTO [users] (uid,first_name,last_name,email,password,gender,is_active,reg_date) VALUES (NEWID(),@fname,@lname,@email,@password,@gender,1,GETDATE())ENDStored procedure to return id of last inserted record:@id int … Read more

In this blog, we will see some of the important SQL Interview Questions and Answers. 1. What is a Primary Key? The primary key is used to uniquely identify a record. A table can not have more than one primary key.If a table has userid, email, passport no. and userid is the primary key then how to maintain the … Read more

sp_addlinkedserver linked 2 servers. Once sp_addlinkedserver query executes, query can be run against these servers. Run below queries one by one to link, to provide login credentials and to access data EXEC sp_addlinkedserver @server=’ServerName’ EXEC sp_addlinkedsrvlogin ‘ServerName‘, ‘false’, NULL, ‘username’, ‘password’ select * from [ServerName].[DBName].[DBO].[TableName] Once your requirement is done, you may drop the linking by … Read more

If someone wants to get data from 2 tables from 2 different SQL DB server. Then execute below stored procedures before running your query. Step1: exec sp_addlinkedserver    @server=db-server-name Step2: EXEC sp_addlinkedsrvlogin db-server-name, false, NULL, id, password Once you executed above SPs successfully, you can check linked server list by executing below SP. exec sp_linkedservers

I found below error while restoring a database to Microsoft SQL Server 2012.System.Data.SqlClient.SqlError: The operating system returned the error 5(Access is denied.) I solved this problem by doing below step:In restore window, from left side pane click on FilesThen in properties please ensure that “Relocate all files to folder” is checked. Try this, i resolved … Read more

In sql there are many options to generate unique number. Here I am explaining about how to generate standard unique number in sql. Below is sql query : CREATE TABLE dbo.tblTable1  (ID INT IDENTITY(1,1) NOT NULL PRIMARY KEY CLUSTERED,   UserID AS UID + RIGHT(00000000 + CAST(ID AS VARCHAR(8)), 8) PERSISTED,   username varchar(200),city varchar(200)  )