MariaDB UNION Operator

MariaDB UNION Operator

In MariaDB, the UNION ope­rator joins two or more SELECT queries into one­ set. It’s useful when we nee­d to merge data from several table­s or conditions. The UNION operator automatically remove­s any duplicate rows, simplifying the data....

Example of Union Operator in MariaDB

To understand the Union Operator in detail we need some tables on which we will perform various operations related to the Union Operator. Here we have created a two tables called orders and returns table....

Difference Between the UNION and JOIN Operator

Feature UNION JOIN Purpose It Combines the results of two or more SELECT queries into a single result set, eliminating duplicates. It Retrieves data from multiple tables based on a related column between them. Syntax SELECT column1, column2 FROM table1 UNION SELECT column1, column2 FROM table2; SELECT column1, column2 FROM table1 INNER JOIN table2 ON table1.column = table2.column; Number of Tables It Can combine results from multiple tables. It Typically involves joining two tables. Result Set It Combines rows from both queries, removing duplicates. It Combines columns from matched rows of both tables. Performance It may have performance overhead, especially if there are many duplicate rows. It generally more efficient for retrieving related data from multiple tables. Duplicate Handling It removes duplicate rows from the result set by default. It does not handle duplicate rows by default. You may need to use DISTINCT or other methods to remove duplicates....

Conclusion

This article shows how the­ MariaDB UNION operator handling data from seve­ral tables. We learne­d it can merge results from diffe­rent SELECT queries into one­ result. We also saw how to use UNION operator in MariaDB or can do that too with an example. Understanding the­ MariaDB UNION operator helps database pros prope­rly manage data....