subquery with joins in mysql code example
Example 1: types of joins in mysql
Joins are used with select statement. it is used to select data from multiple table.
Types:
MySQL INNER JOIN (or simple join)
MySQL LEFT OUTER JOIN (or LEFT JOIN)
MySQL RIGHT OUTER JOIN (or RIGHT JOIN)
Inner JOIN :
The INNER JOIN is used to return all rows from multiple tables where the join condition is satisfied. It is the most common type of join.
Left Outer Join:
The LEFT OUTER JOIN returns all rows from the left hand table specified in the ON condition and only those rows from the other table where the join condition is fulfilled.
Right Outer Join:
The Right Outer Join returns all rows from the RIGHT-hand table specified in the ON condition and only those rows from the other table where he join condition is fulfilled.
Example 2: mysql two joins
SELECT areas.name AS aname, COUNT(consultants.active) AS cct
FROM areas
LEFT JOIN consAreas
ON consAreas.area = areas.id
LEFT JOIN consultants
ON consultants.id = consAreas.cons
WHERE areas.areaID = $area
AND consultants.active = 1
GROUP BY areas.name
ORDER BY areas.name