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This tutorial shows you how to use the Oracle UNION to combine result sets of multiple queries. The UNION removes duplicate while the UNION ALL does not.
You can combine multiple queries using the set operators UNION, UNION ALL, INTERSECT, and MINUS. All set operators have equal precedence. If a SQL statement contains multiple set operators, then Oracle Database evaluates them from the left to right unless parentheses explicitly specify another order.
8 Σεπ 2008 · Both UNION and UNION ALL concatenate the result of two different SQLs. They differ in the way they handle duplicates. UNION performs a DISTINCT on the result set, eliminating any duplicate rows. UNION ALL does not remove duplicates, and it therefore faster than UNION.
This Oracle tutorial explains how to use the Oracle UNION operator with syntax and examples. The Oracle UNION operator is used to combine the result sets of 2 or more Oracle SELECT statements. It removes duplicate rows between the various SELECT statements.
The set operators union, intersect, and minus allow you to combine many tables into one. This tutorial will use these two tables for the queries: select * from my_brick_collection; select * from your_brick_collection;
In this tutorial, we will be learning about the UNION and UNION ALL set operator in Oracle. The set operators work on the same principle as set operators in mathematics. Before we begin understanding the set operators in Oracle, lets revisit the concept of set operators in Maths through this example: Here, A and B are two sets containing numbers.
The UNION operator is used to combine the result-set of two or more SELECT statements. The UNION operator selects only distinct values by default. To allow duplicate values, use UNION ALL: Note: The column names in the result-set are usually equal to the column names in the first SELECT statement.
