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.

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:

CriteriaCross JoinLeft Outer Join
SyntaxSELECT * FROM table1 CROSS JOIN table2;SELECT * FROM table1 LEFT JOIN table2 ON table1.column = table2.column;
PurposeReturns the Cartesian product of two tablesReturns all the rows from the left table and matching rows from the right table
Matching criteriaNo matching criteria requiredMatching criteria is required
Null valuesGenerates null values for non-matching rowsReturns null values for non-matching rows in the right table
Result sizeThe result size is the product of the number of rows in both tablesThe result size is the number of rows in the left table
Use caseUsed when we need to combine all the rows from two tablesUsed 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.

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