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Confused in Right join and Left Join and inner join and outer join

29th Nov 2016, 5:53 PM
Anshul Jain
Anshul Jain - avatar
2 ответов
+ 2
Inner join returns the matching records from two tables, according to the join condition. From the course: "The LEFT JOIN returns all rows from the left table, even if there are no matches in the right table. " So the dominant table is the one in the left. The right join is essentially the same as the left join, except that the dominant table is the right one. Outer join is either left join or right join. Inner join is the opposite from outer join.
29th Nov 2016, 6:47 PM
Álvaro
0
Outer joins; the key words LEFT or RIGHT point to the "anchor" table where you expect all matching rows, the other table may contain the NULL records. As with FULL OUTER JOIN you expect NULL records on both sides of a table join.
20th Dec 2016, 9:05 PM
Stephan Borsodi
Stephan Borsodi - avatar