Combining tables is one of the most common and useful operations in SQL. Whether you are analyzing data, generating reports, or just cleaning up datasets, knowing how to write an SQL query to combine two tables is an essential skill. In this guide, we’ll explain step-by-step methods for combining tables, examples with sample data, and how AI-powered tools like AI2sql can assist you in this process.

Why Combine Two Tables in SQL?

Data is often distributed across multiple tables in a database. To get meaningful insights, you often need to merge or combine these tables. Common scenarios include:

• Joining customer data with order details

• Connecting employee records with department information

• Linking sales data from different sources

Popular Methods to Combine Two Tables

The method you choose depends on the relationship between the tables and the information you want to extract. Here are the main SQL techniques used:

1. Using JOIN Statements

• INNER JOIN: Returns records with matching values in both tables.

• LEFT JOIN: Returns all records from the left table and matching records from the right table.

• RIGHT JOIN: Returns all records from the right table and matching records from the left table.

• FULL JOIN: Returns records when there is a match in either left or right table.

Example: SQL Query to Combine Two Tables Using INNER JOIN

-- Table: Customers
-- Columns: CustomerID, CustomerName
-- Table: Orders
-- Columns: OrderID, CustomerID, OrderDate

SELECT Customers.CustomerName, Orders.OrderID, Orders.OrderDate
FROM Customers
INNER JOIN Orders ON Customers.CustomerID = Orders.CustomerID;

This example retrieves the names of customers and their corresponding order IDs and dates.

2. Using UNION

If you wish to append rows from both tables (and both have the same structure), you can use UNION:

SELECT column1, column2 FROM Table1
UNION
SELECT column1, column2 FROM Table2;

Note: UNION removes duplicates. Use UNION ALL to include all records.

How AI2sql Simplifies Combining SQL Tables

Writing SQL queries can be time-consuming, especially if you’re not an SQL expert. AI2sql lets you generate complex SQL queries with plain English. Simply describe what you need—for example:

Combine customers and their orders, showing customer names and order dates.

AI2sql instantly converts your request into a precise SQL query, helping you:

• Save time

• Avoid syntax errors

• Focus on analysis, not query writing

Interested in learning more? Check out our blog for additional SQL tips and AI-powered tools!

Final Tips for Working with SQL Joins

• Always be clear about the type of join you need

• Check your data for matching keys between tables

• Test your queries with sample data

• Use descriptive aliases for readability

Conclusion

Combining two tables using SQL is a fundamental skill for anyone working with data. With a clear understanding of JOINs and UNION, and the help of AI2sql, you can boost your productivity and focus on gathering insights. Ready to simplify your SQL workflows? Try AI2sql for free and experience effortless query generation!