In Oracle, INTERSECT Operator is used to return the results of 2 or more SELECT statement. It picks the common or intersecting records from compound SELECT queries.
Syntax
SELECT expression1, expression2, ... expression_n
FROM table1
WHERE conditions
INTERSECT
SELECT expression1, expression2, ... expression_n
FROM table2
WHERE conditions;
Parameters
1) expression1, expression2, … expression_n: It specifies the columns that you want to retrieve.
2) table1, table2: It specifies the tables that you want to retrieve records from.
3) conditions: it specifies the conditions that must be fulfilled for the records to be selected.
Oracle INTERSECT Example: (with single expression)
Suppliers Table
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Suppliers Data
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Order_details Table
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Order_details Data
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SELECT supplier_id
FROM suppliers
INTERSECT
SELECT supplier_id
FROM order_details;
In the above example, the supplier_id appears in both the suppliers and order_details table. Now the common entries will be returned in the result set.
Output
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Oracle INTERSECT Example: (with multiple expressions)
Supplier Table
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Supplier Data
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Customer Table
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Customer Data
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SELECT supplier_id, last_name, first_name
FROM supplier
WHERE first_name <> 'dhirubhai'
INTERSECT
SELECT customer_id, last_name, first_name
FROM customer
WHERE customer_id < 5;
Output
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The above example returns the records from the supplier table where the supplier_id, last_name and first_name values match the customer_id, last_name, and first_name value of customer table.
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