Concept explainers
What is a cross join? Give an example of its syntax.
Join:
Join is a relational operation, which combines the data from two or more tables into single table or view, then that is called as Join.
Explanation of Solution
CROSS join:
- It is a type of join operation that performs Cartesian product of two tables.
- That is, it produces a result set in which the rows from first table are multiplied with the rows from second table.
Syntax:
SELECT * FROM table_1 CROSS JOIN table_2;
Example:
Table creation:
Creating table 1:
CREATE TABLE table_1 (Item_ID int, Item_Name varchar(10), Company_ID int primary key);
Creating table 1:
CREATE TABLE table_2 (Company_ID int references table_1, Company_Name varchar(10), Company_city varchar(10));
Inserting values:
Inserting values to table 1:
INSERT INTO table_1 values (1, "Pancakes", 101);
INSERT INTO table_1 values (2, "Rice", 109);
INSERT INTO table_1 values (3, "Cakes", 106);
Inserting values to table 1:
INSERT INTO table_2 values (106, "AAA", "ZZZ");
INSERT INTO table_2 values (109, "BBB", "YYY");
Query using “CROSS JOIN”:
SELECT * FROM table_1 CROSS JOIN table_2;
Screenshot of the result:
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Chapter 7 Solutions
DATABASE SYSTEMS (LOOSELEAF)-W/MINDTAP
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