How to convert DATETIME to VARCHAR in Microsoft SQL Server? Example Tutorial

One of the most common, yet trick for many programmer, is to convert a DATETIME column into VARCHAR i.e. String in SQL Server. Suppose, in People table, you have a datetime column, birthdate and you want to print the name and birthdate into dd-MM-yyyy format, you need to convert the datetime column into varchar. You can use the CONVERT() function to do this job. It accepts three arguments, the data, the output type and the format in which you want your VARCHAR date e.g. to convert birthdate of a person into dd-MM-yyyy, we need to use the formatting style 1.

What is Primary key in SQL? How to choose Primary key in table? Example

If you've ever dealt with databases, you've almost certainly come across the term - primary key (PK). And if you're following this series to learn about databases, this piece should help you understand what the PK is all about. Even if you're a database specialist, you could learn something new or improve your skills. So sit back, relax, and let's get started with the PKs.

How to get rows between two dates in Microsoft SQL Server? MSSQL Example

Problem: You want all records between two dates e.g. start_date and end_date. For example, you have a Course table, which contains course_name, price and start_date. If want all the course which are starting next month, how will you do that?

Solution : You can get the records between two dates in SQL SERVER by using dates in WHERE clause, for example, below query will return all the courses for which start date is greater than 2025/01/01 and less than 2025/01/31

How to Remove duplicate rows from table in SQL Server using temp table? Example

One of the easiest way to remove duplicate rows from a table in SQL is copy unique data into temp table, delete the original table and create a new table from the temp table without any duplicates. Sometime when you don't have a unique key or primary key in table, you end up with duplicate rows i.e. more than one rows where all columns are identical. You can easily find those duplicate rows by using GRPUP BY, as seen in our previous SQL interview questions. You can also print just unique rows by using distinct clause, but how do you go about removing duplicate rows from table altogether? That's what you will learn in this article. Actually there are multiple ways to remove duplicates and you will learn couple of them in this article. 

Difference between Primary key Unique key in Database SQL

Hello friends, both primary key and unique key are two important concepts in a relational database which are used to uniquely identify a row in a table. For example, EmployeeId is often primary key in Employee table which can uniquely identify any employee which is denoted by a row in Employee table. Similarly, a employee can also be identify with EmployeeName if there is no duplicate but if its not primary key then we call it a unique key. While both primary key and unique keys can identify a row uniquely but there is some subtle difference between them which we will see in this article.