SQL Syntax

SQL Syntax

I hope you guys have gone through my previous tutorial SQL – A database language. Now let’s move little bit further to write basic SQL queries.

Since you guys are beginners in SQL, i am going to start with a basic SQL query syntax. Later we will go through lots of complex syntax.

— Basic SQL Query Syntax

SELECT <Column Names>

FROM <Table Name>

WHERE <Filter Condition>

GROUP BY <Column Name>

HAVING <Filter Condition>

ORDER BY <Column Name> ASC/DESC

Explanation:

Line 1: This is Single line comment in SQL. This will not be executed. To comment multiple lines at a time(block comment), include the text to be commented in between /* and */

Line 2: Select list consists of the required column names data to be displayed. To display all columns data, use SELECT *

Line 3: List of table names from which data to be fetched.

Line 4: Condition to filter the data.

Line 5: To group the data based on columns.

Line 6: Condition to filter the data when aggregate functions are used in select list.

Line 7: To sort the data in ascending or descending order. By default it is ascending.

Simple Example

— Example: To fetch EmployeeID and EmployeeName values of dbo.Employee table.

SELECT EmployeeName,Designation, Sum(Sal)

FROM dbo.Employee

WHERE EmployeeID IN (1,2,3)

GROUP BY EmployeeName,Designation

HAVING COUNT(EmployeeName) = 1

ORDER BY EmployeeID DESC

Well. We are able to write basic query in SQL :)  Before writing queries further, remember writing queries that provide you with the required result is not the only thing required but following the standards also equally important :) I am going to discuss database standards to be followed while writing SQL queries in my coming tutorials.

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