JOIN in SQL is used to combine data from many tables based on a matched condition between them. The data combined using JOIN statement results into new columns.
Consider the two tables:
sql> SELECT Boys.Name, Boys.Age, Girls.Address, FROM Boys INNER JOIN Girls ON Boys.Rollno = Girls.Rollno;
The resultant table is:
UNION in SQL is used to combine the result-set of two or more SELECT statements. The data combined using UNION statement is into results into new distinct rows.
sql> SELECT Name FROM Boys WHERE Rollno < 16 UNION SELECT Name FROM Girls WHERE Rollno > 9
The resultant table is:
Difference between JOIN and UNION in SQL :
|JOIN combines data from many tables based on a matched condition between them.||SQL combines the result-set of two or more SELECT statements.|
|It combines data into new columns.||It combines data into new rows|
|Number of columns selected from each table may not be same.||Number of columns selected from each table should be same.|
|Datatypes of corresponding columns selected from each table can be different.||Datatypes of corresponding columns selected from each table should be same.|
|It may not return distinct columns.||It returns distinct rows.|
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Improved By : dhruv5819