SQL Challenge: C-01


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SQL Day 11: Group By in SQL Server

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LO1: Grouping rows using Group By LO2: Filtering Groups LO3: Difference between Where and Having Clause Group By clause is used to group a selected set of rows into a set of summary rows by the values of one or more columns or expression. It is always used in conjunction with one or more aggregate functions. Let’s say we have a table tblEmployee which contains all the salary of employees including the cities. So if we need to find the maximum salary of employee we can use the MAX(Column_Name) aggregate function to find the highest salary of employees. select MAX(salary) from tblemployee In the same way, we can find the minimum salary and total salary of all the employees using different aggregate functions. select MIN(salary) as [Minimum Salary] from tblemployee select SUM(salary) as [Total Salary] from tblemployee Let’s say we have to find out the employee salary as per the different cities, to achieve this we need to use the Group B...
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SQL Day 2: Creating, Altering and Dropping a Database

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LO1: Creating, Altering and Dropping a Database Prerequisite:   Connecting to SQL Server using SSMS After connecting to the database through SSMS first we need to create the database on which different queries will run. Let’s start with creating a Database. A SQL Server Database can be Created, Altered or Dropped in two ways: Graphically using SQL Server Management Studio or Using SQL Query Graphically using SQL Server Management Studio: Within the Object Explorer, right-click on Database folder and select the New Database. When clicked on New Database a new dialog box will open. Here you need to provide the database name and when clicking on OK, SQL Server run the query internally and will create the new database for us. When you expand the database folder then you will see the Sample database here Creating Database Using Query: We can also create the database by executing the query in the query editor. For creating a...
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SQL Day 3: Creating Tables & Enforcing Primary and Foreign Key

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LO1: Creating the Tables LO2: Enforcing Primary and Foreign Key Prerequisite: Creating a Database Creating Tables You can create a table by two ways. By Graphically : Expand the Database in Object Explorer and right click on Tables folder and click on New Table Give the Column Name, Data Type and check Allow Nulls. Column Name: This is going to be your column name and this column name should be unique in the table. Data Type: For which type of data will be contained in the column. For example int, nvarchar, float, image etc. Allow Nulls: This is a check box which tells us that the column will contain null values or not. Primary Key allows you to uniquely identify the row in the table and it does not allow null. Must Remember: Primary key can be applied to one single column or group of the column to uniquely identify a record/row in the table but only one primary key allows in the table. To make the primary key graphically y...
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