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The UNION operator selects only distinct values by default. To allow duplicate values, use UNION ALL: SELECT column_name (s) FROM table1. UNION ALL. SELECT column_name (s) FROM table2; Note: The column names in the result-set are usually equal to the column names in the first SELECT statement.
This tutorial shows you how to use the MySQL UNION operator to combine results of two or more queries into a single result set.
UNION combines the result from multiple query blocks into a single result set. This example uses SELECT statements: mysql> SELECT 1, 2; +---+---+ | 1 | 2 | +---+---+ | 1 | 2 | +---+---+ mysql> SELECT 'a', 'b'; +---+---+ | a | b | +---+---+ | a | b | +---+---+ mysql> SELECT 1, 2 UNION SELECT 'a', 'b'; +---+---+ | 1 | 2 | +---+---+ | 1 | 2 | | a ...
UNION: Combine all results from two query blocks into a single result, omitting any duplicates. INTERSECT: Combine only those rows which the results of two query blocks have in common, omitting any duplicates. EXCEPT: For two query blocks A and B, return all results from A which are not also present in B, omitting any duplicates.
19 lip 2024 · One powerful Operator in MySQL for combining results from multiple queries is the UNION operator. This operator allows you to merge the results of two or more SELECT statements into a single result set, eliminating duplicate rows by default.
The UNION operator in MySQL is used to combine the result sets of two or more SELECT statements into a single result set. This can be useful when you want to retrieve and display data from multiple tables or queries as if it were coming from a single source.
The MySQL UNION operator is used to combine the result sets of 2 or more SELECT statements. It removes duplicate rows between the various SELECT statements. Each SELECT statement within the UNION operator must have the same number of fields in the result sets with similar data types.
