В следующем примере показаны случаи правильного и неверного использования UNION в двух инструкциях SELECT, в которых необходимо переименовать столбцы на выходе.

Для корректной работы UNION нужно, чтобы результирующие таблицы каждого из SQL запросов имели одинаковое число столбцов, с одним и тем же типом данных и в той же …

The UNION operator is used to combine the result-set of two or more SELECT statements. The UNION operator automatically removes duplicate rows from the result set.

Nov 17, 2025 · The SQL UNION operator is used to combine the result sets of two or more SELECT queries into a single output. It removes duplicate rows and returns only unique …

This SQL tutorial explains how to use the SQL UNION operator with syntax and examples. The SQL UNION operator is used to combine the result sets of 2 or more SELECT statements.

Jul 20, 2017 · Оператор UNION подобно inner join или outer join позволяет соединить две таблицы. Но в отличие от inner/outer join объединения соединяют не столбцы разных …

SQL UNION operator allows users to combine the results of two or more SELECT statements into a single result set. The UNION operator returns only distinct values by default, making it a …

Is it possible to select from the result of a union? For example I'm trying to do something like: SELECT A FROM ( SELECT A, B FROM TableA UNION SELECT A, B FROM TableB ) …

The UNION operator in SQL selects fields from two or more tables. In this tutorial, you will learn about the SQL UNION operator with the help of examples.

Вы можете использовать UNION для объединения любого количества запросов SELECT, объединяя их результаты.

The UNION operator combines the results of two SELECT statements into a single result set. If the ALL parameter is given, all the duplicates of the rows returned are retained; otherwise the …

In summary, the UNION operator in SQL Server is a useful tool for combining the results of multiple SELECT statements into a single result set. It allows you to retrieve data from …

Note: If some customers or suppliers have the same city, each city will only be listed once, because UNION selects only distinct values. Use UNION ALL to also select duplicate values!

The SQL UNION operator is used to combine the result sets of two or more SELECT queries into a single result set. Each query within the UNION must have the same number of columns in …

Nov 20, 2024 · Q: What is the purpose of the SQL UNION operator? A: The SQL UNION operator is used to combine the results of two or more SELECT statements, providing a way to merge …

6.4.1.2 Синтаксис оператора UNION 6 Справочник по языку MySQL 6.4 Обработка данных: SELECT, INSERT, UPDATE, DELETE 6.4.1 Синтаксис оператора SELECT 6.4.1.1 …

Nov 18, 2025 · When any SELECT statement in a UNION statement includes an ORDER BY clause, that clause should be placed after all SELECT statements. The following example …

Dec 21, 2023 · UNION combines the result sets of two SELECT queries. The data type and order of the columns in these queries must match. SQL UNION returns only unique rows. SQL …

Aug 4, 2025 · The UNION keyword enables you to include the results of two SELECT statements in one resulting table. All rows returned from either SELECT statement are combined into the …

Nov 22, 2024 · This code selects all students with an age less than 15, orders them by name, and then combines them with the results of the second SELECT statement using UNION.