SQL Server Cross Join vs Left Outer Join

In this SQL Server tutorial, we will learn everything about SQL Server Cross Join vs Left Outer Join.

SQL Server is a popular relational database management system that provides several types of join operations to combine data from two or more tables. Two commonly used types of join operations in SQL Server are Cross Join and Left Outer Join. Although they may seem similar, they have different functionalities and are used in different scenarios. In this article, we will compare SQL Server Cross Join vs Left Outer Join and discuss their differences and use cases.

Table of Contents

Comparison of SQL Server Cross Join vs Left Outer Join

The following table provides a comparison of SQL Server Cross Join vs Left Outer Join:

Criteria	Cross Join	Left Outer Join
Syntax	SELECT * FROM table1 CROSS JOIN table2;	SELECT * FROM table1 LEFT JOIN table2 ON table1.column = table2.column;
Purpose	Returns the Cartesian product of two tables	Returns all the rows from the left table and matching rows from the right table
Matching criteria	No matching criteria required	Matching criteria is required
Null values	Generates null values for non-matching rows	Returns null values for non-matching rows in the right table
Result size	The result size is the product of the number of rows in both tables	The result size is the number of rows in the left table
Use case	Used when we need to combine all the rows from two tables	Used when we need to combine all the rows from the left table and matching rows from the right table

Conclusion

SQL Server Cross Join and Left Outer Join are two different types of join operations that serve different purposes. Cross Join returns the Cartesian product of two tables, while Left Outer Join returns all the rows from the left table and matching rows from the right table.

Cross Join does not require matching criteria and generates null values for non-matching rows, while Left Outer Join requires matching criteria and returns null values for non-matching rows in the right table.

Cross Join generates a larger result set than Left Outer Join, and it is used when we need to combine all the rows from two tables. Left Outer Join is used when we need to combine all the rows from the left table and matching rows from the right table.