{"id":106096,"date":"2025-10-15T12:32:54","date_gmt":"2025-10-15T07:02:54","guid":{"rendered":"https:\/\/www.admecindia.co.in\/?p=106096"},"modified":"2025-10-15T12:33:04","modified_gmt":"2025-10-15T07:03:04","slug":"what-is-sql-and-its-queries-which-every-developer-must-know","status":"publish","type":"post","link":"https:\/\/www.admecindia.co.in\/data-science\/what-is-sql-and-its-queries-which-every-developer-must-know\/","title":{"rendered":"What is SQL and Its Queries Which Every Developer Must Know"},"content":{"rendered":"
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Whether you are building a backend of a web application<\/strong> or working with huge datasets<\/strong>, SQL always remain one of the most vital tools for communicating with the databases<\/strong>. It allows you to access, update, and manage the data efficiently<\/strong>, that makes everyday development tasks much faster and well-organized. In this blog, we will walk through 10 SQL queries that every developer<\/strong>, whether you are just starting out or experienced already, must know confidently<\/strong>.<\/p>\n\n\n\n

\"Essential<\/figure>\n\n\n\n
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Who should read it?<\/h2>\n\n\n\n

SQL is language of database and having its knowledge is crucial for better database management<\/strong>. So, if you are using database in your daily work then you must read this blog till the end. This blog is good to read for all professionals from the industries like software development, web development, data science, machine learning, etc. Even if you are a student who is attending training under a data analytics course<\/strong><\/a> or web development course<\/strong><\/a>, this blog is for you.<\/p>\n\n\n\n

So, dear data analysts, web developers, software developers, and individuals interested in database administration, let\u2019s get ready to know SQL queries.<\/p>\n\n\n\n

What is SQL?<\/h2>\n\n\n\n

SQL known as \u201cStructured Query Language<\/strong>\u201d. This programming language is capable of handling interactions with various types of relational databases<\/strong><\/a>.<\/p>\n\n\n\n

With the rise of digitalization and massive data production<\/strong>, it is crucial to manage and manipulate data in a well-organized manner to obtain underlying information.<\/p>\n\n\n\n

Essential SQL Queries Every Developer Must Know<\/h2>\n\n\n\n

Let\u2019s start with this blog post on SQL Queries to understand what they are, including 10 essential questions.<\/p>\n\n\n\n

So, now here we are getting started:<\/p>\n\n\n\n

Query #1 | SELECT Statement<\/h3>\n\n\n\n

The SELECT Query is a powerful query that fetches data from multiple tables<\/strong> easily. There are various applications which use this query, one way is below:<\/p>\n\n\n\n

Example of SELECT Statement:<\/h4>\n\n\n\n
SELECT empName, empAddress, empSalary FROM employee_details;<\/pre>\n\n\n\n
Explanation:<\/strong> This query fetches the employee\u2019s name, employee\u2019s address, and employee\u2019s salary of all employees exists in the employee_details table.<\/p>\n\n\n\n
When to use SELECT Statement:<\/h4>\n\n\n\n
When your task is to fetch any type of information that exist in one or more tables of a database.<\/p>\n\n\n\n
Best Practices:<\/h4>\n\n\n\n
Always try to fetch specific records or the content you desire, rather than fetching all records with all columns for better performance.<\/p>\n\n\n\n
Example:<\/h4>\n\n\n\n
SELECT name, age FROM students;<\/pre>\n\n\n\n
Explanation:<\/strong> It retrieves only name, age columns from student table.<\/p>\n\n\n\n
Query #2 | WHERE Statement<\/h3>\n\n\n\n
The WHERE Statement is used to help SELECT Statement in filtering records<\/strong>, so that only desired results are being fetched using Operators, and different types of Clauses<\/strong>.<\/p>\n\n\n\n
Example of WHERE Statement:<\/h4>\n\n\n\n
SELECT salary FROM employees_table WHERE deptName like 'S%';<\/pre>\n\n\n\n
Explanation<\/strong>: This query fetches the salaries of those employees whose department name\u2019s first letter is \u2018S\u2019.<\/p>\n\n\n\n
When to use WHERE Statement:<\/h4>\n\n\n\n
You should use WHERE Statement when you want to fetch specific records based on some condition. Also, you can use different type of relational operators<\/strong> like <, >, <=, <=; and clauses like BETWEEN, AND, OR, IN, etc.<\/p>\n\n\n\n
Best Practices: <\/strong>It is recommended not to use WHERE Statement with aggregate functions such as AVG, MIN, MAX, SUM, COUNT, etc.<\/p>\n\n\n\n
Query #3 | INSERT INTO Statement<\/h3>\n\n\n\n
The INSERT INTO statement is used to add new entries to a table. It allows you to populate your database with fresh data<\/strong>, such as new users, products, or any form of structured information.<\/p>\n\n\n\n
Example of INSERT INTO Statement:<\/h4>\n\n\n\n
INSERT INTO employees_table (empName, deptName, empPosition) VALUES ('John Doe', 'Sales', 'Sales Manager');<\/pre>\n\n\n\n
Explanation:<\/strong> This query inserts a record in a table named employees_table specifically in three columns named \u201cempName, deptName, and empPosition\u201d with record values \u201cJohn Doe\u201d, \u201cSales\u201d, and \u201cSales Manager\u201d.<\/p>\n\n\n\n
When to use INSERT INTO Statement:<\/h4>\n\n\n\n
You can use INSERT INTO when you\u2019re storing new data into tables in a database<\/strong> like during user registration or when adding new product items to an inventory.<\/p>\n\n\n\n
Best Practice:<\/strong><\/p>\n\n\n\n