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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: SELECT product_id FROM order_items UNION SELECT product_id FROM inventories ORDER BY product_id; SELECT location_id FROM locations UNION ALL SELECT location ...
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.
This Oracle tutorial explains how to use the Oracle UNION ALL operator with syntax and examples. The Oracle UNION ALL operator is used to combine the result sets of 2 or more SELECT statements (does not remove duplicate rows).
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.
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.
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.
UNION ALL Example. 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:
