Set operators - Amazon OpenSearch Service

Set operators

Note

To see which AWS data source integrations support this SQL command, see Supported OpenSearch SQL commands and functions.

Set operators are used to combine two input relations into a single one. OpenSearch SQL supports three types of set operators:

  • EXCEPT or MINUS

  • INTERSECT

  • UNION

Input relations must have the same number of columns and compatible data types for the respective columns.

EXCEPT

EXCEPT and EXCEPT ALL return the rows that are found in one relation but not the other. EXCEPT (alternatively, EXCEPT DISTINCT) takes only distinct rows while EXCEPT ALL does not remove duplicates from the result rows. Note that MINUS is an alias for EXCEPT.

Syntax 

 [ ( ] relation [ ) ] EXCEPT | MINUS [ ALL | DISTINCT ] [ ( ] relation [ ) ]

Examples

-- Use table1 and table2 tables to demonstrate set operators in this page.
SELECT * FROM table1;
+---+
|  c|
+---+
|  3|
|  1|
|  2|
|  2|
|  3|
|  4|
+---+
SELECT * FROM table2;
+---+
|  c|
+---+
|  5|
|  1|
|  2|
|  2|
+---+
SELECT c FROM table1 EXCEPT SELECT c FROM table2;
+---+
|  c|
+---+
|  3|
|  4|
+---+
SELECT c FROM table1 MINUS SELECT c FROM table2;
+---+
|  c|
+---+
|  3|
|  4|
+---+
SELECT c FROM table1 EXCEPT ALL (SELECT c FROM table2);
+---+
|  c|
+---+
|  3|
|  3|
|  4|
+---+
SELECT c FROM table1 MINUS ALL (SELECT c FROM table2);
+---+
|  c|
+---+
|  3|
|  3|
|  4|
+---+

INTERSECT

INTERSECT and INTERSECT ALL return the rows that are found in both relations. INTERSECT (alternatively, INTERSECT DISTINCT) takes only distinct rows while INTERSECT ALL does not remove duplicates from the result rows.

Syntax 

 [ ( ] relation [ ) ] INTERSECT [ ALL | DISTINCT ] [ ( ] relation [ ) ]

Examples

(SELECT c FROM table1) INTERSECT (SELECT c FROM table2);
+---+
|  c|
+---+
|  1|
|  2|
+---+
(SELECT c FROM table1) INTERSECT DISTINCT (SELECT c FROM table2);
+---+
|  c|
+---+
|  1|
|  2|
+---+
(SELECT c FROM table1) INTERSECT ALL (SELECT c FROM table2);
+---+
|  c|
+---+
|  1|
|  2|
|  2|
+---+

UNION

UNION and UNION ALL return the rows that are found in either relation. UNION (alternatively, UNION DISTINCT) takes only distinct rows while UNION ALL does not remove duplicates from the result rows.

Syntax 

 [ ( ] relation [ ) ] UNION [ ALL | DISTINCT ] [ ( ] relation [ ) ]

Examples

(SELECT c FROM table1) UNION (SELECT c FROM table2);
+---+
|  c|
+---+
|  1|
|  3|
|  5|
|  4|
|  2|
+---+
(SELECT c FROM table1) UNION DISTINCT (SELECT c FROM table2);
+---+
|  c|
+---+
|  1|
|  3|
|  5|
|  4|
|  2|
+---+
SELECT c FROM table1 UNION ALL (SELECT c FROM table2);
+---+
|  c|
+---+
|  3|
|  1|
|  2|
|  2|
|  3|
|  4|
|  5|
|  1|
|  2|
|  2|
+---+