10 SQL Queries Every Developer Should Know

SQL (Structured Query Language) is a cornerstone of database management and an essential skill for developers. Knowing how to write efficient queries can make or break your application's performance. Here, we present 10 must-know SQL queries that every developer should have in their toolkit, along with explanations and practical examples.

1. Select All Columns from a Table

      SELECT * FROM table_name;
      

2. Select Specific Columns

      SELECT column1, column2 FROM table_name;
      

3. Filtering Results with WHERE

      SELECT * FROM table_name WHERE condition;
      

4. Using Aggregate Functions

      SELECT COUNT(*), AVG(column_name), SUM(column_name) FROM table_name;
      

5. Grouping Data with GROUP BY

      SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name;
      

6. Sorting Results with ORDER BY

      SELECT * FROM table_name ORDER BY column_name ASC;
      

7. Joining Tables

      SELECT a.column1, b.column2 FROM table1 a
      INNER JOIN table2 b ON a.common_column = b.common_column;
      

8. Using Subqueries

      SELECT column_name FROM table_name
      WHERE column_name = (SELECT column_name FROM another_table WHERE condition);
      

9. Inserting Data

      INSERT INTO table_name (column1, column2) VALUES (value1, value2);
      

10. Updating Data

      UPDATE table_name SET column1 = value1 WHERE condition;
      

Conclusion

These SQL queries form the foundation of database interaction. Mastering them will enhance your productivity and ensure your applications handle data efficiently. Which query do you find most essential in your work? Let us know in the comments!