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Databases Querying Relational Databases Set Operations Review and Practice

Angel Avendaño
Angel Avendaño
5,013 Points
Posted by Angel Avendaño
Angel Avendaño
5,013 Points

Count the total of rows in the result query when UNION is present

In the first exercice "Find All Books" , when I run:

SELECT * FROM books_north UNION ALL SELECT * FROM books_south;

Where do I have to put 'COUNT' in the query to get the total rows in it?

1 Answer

Dale Severude
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Dale Severude
Full Stack JavaScript Techdegree Graduate 71,349 Points
Dale Severude
.a{fill-rule:evenodd;}techdegree seal-36
Dale Severude
Full Stack JavaScript Techdegree Graduate 71,349 Points

Hi Angel,

To get the count of a union operation I would put the count outside of the query like so:

select count(*) from (select title from books_north union select title from books_south);