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UNION ALL Syntax. 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.
The UNION operator is a set operator that combines result sets of two or more SELECT statements into a single result set. The following illustrates the syntax of the UNION operator that combines the result sets of two queries: SELECT column_list_1 FROM T1 UNION SELECT column_list_1 FROM T2; Code language: SQL (Structured Query Language) (sql)
The UNION operator returns only distinct rows that appear in either result, while the UNION ALL operator returns all rows. The UNION ALL operator does not eliminate duplicate selected rows:
25 Σεπ 2018 · The Union operator combines the results of two or more queries into a distinct single result set that includes all the rows that belong to all queries in the Union. In this operation, it combines two more queries and removes the duplicates. For example, the table ‘A’ has 1,2, and 3 and the table ‘B’ has 3,4,5.
8 Σεπ 2008 · The UNION ALL command is equal to the UNION command, except that UNION ALL selects all values. The difference between Union and Union all is that Union all will not eliminate duplicate rows, instead it just pulls all rows from all tables fitting your query specifics and combines them into a table.
24 Ιουλ 2024 · The SQL UNION operator combines the result sets of two or more SELECT queries. UNION returns unique rows, eliminating duplicate entries from the result set. UNION ALL includes all rows, including duplicate rows. Columns in the result set must be in the same order and have the same data types.
In SQL terms, the UNION operator allows us to combine the result sets of two or more SELECT statements. Here's the basic syntax: SELECT column1, column2, ... FROM table1 UNION SELECT column1, column2, ... FROM table2; Remember, for UNION to work properly: The number of columns in each SELECT statement must be the same.
