{"id":13191,"date":"2024-03-15T02:02:27","date_gmt":"2024-03-15T02:02:27","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-to-merge-query-results-in-oracle\/"},"modified":"2025-08-05T13:14:03","modified_gmt":"2025-08-05T13:14:03","slug":"how-to-merge-query-results-in-oracle","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-to-merge-query-results-in-oracle\/","title":{"rendered":"Merge Oracle Query Results: UNION vs UNION ALL"},"content":{"rendered":"

In Oracle, you can merge query results into one result set using the UNION or UNION ALL keywords.<\/p>\n

The UNION keyword is used to combine the result sets of two or more SELECT statements and eliminates duplicate rows. The syntax is as follows:<\/p>\n

SELECT \u5217\u540d1, \u5217\u540d2, ... FROM \u8868\u540d1\r\nUNION\r\nSELECT \u5217\u540d1, \u5217\u540d2, ... FROM \u8868\u540d2\r\n<\/code><\/pre>\n
The UNION ALL keyword is used to combine the result sets of two or more SELECT statements without removing duplicate rows. The syntax is as follows:<\/p>\n
SELECT \u5217\u540d1, \u5217\u540d2, ... FROM \u8868\u540d1\r\nUNION ALL\r\nSELECT \u5217\u540d1, \u5217\u540d2, ... FROM \u8868\u540d2\r\n<\/code><\/pre>\n
It is important to note that when combining the result sets with UNION or UNION ALL, the number of columns and data types must be the same. If they are different, type conversion functions can be used to handle it.<\/p>\n
Here is an example:<\/p>\n
SELECT name, age FROM table1\r\nUNION\r\nSELECT name, age FROM table2\r\n<\/code><\/pre>\n
This will return a result set that merges and removes duplicate name and age fields.<\/p>\n
SELECT name, age FROM table1\r\nUNION ALL\r\nSELECT name, age FROM table2\r\n<\/code><\/pre>\n
This will return a result set that combines name and age fields without removing any duplicates.<\/p>\n","protected":false},"excerpt":{"rendered":"
In Oracle, you can merge query results into one result set using the UNION or UNION ALL keywords. The UNION keyword is used to combine the result sets of two or more SELECT statements and eliminates duplicate rows. The syntax is as follows: SELECT \u5217\u540d1, \u5217\u540d2, … FROM \u8868\u540d1 UNION SELECT \u5217\u540d1, \u5217\u540d2, … FROM […]<\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[11843,17499,17496,17497,17498],"class_list":["post-13191","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-combine-sql-results","tag-duplicate-rows-oracle","tag-merge-query-results","tag-oracle-union","tag-oracle-union-all"],"yoast_head":"\nMerge Oracle Query Results: UNION vs UNION ALL - Blog - Silicon Cloud<\/title>\n<meta name=\"description\" content=\"Learn to combine Oracle SQL results using UNION\/UNION ALL operators. 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