What is the difference between left joins and right joins in mysql [duplicate]

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What is the difference between Left, Right, Outer and Inner Joins?

What is the difference between l开发者_运维知识库eft joins and right joins in mysql

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The difference is in the way tables are joined if there are no common records.

JOIN is same as INNER JOIN and means to only show records common to both tables. Whether the records are common is determined by the fields in join clause. For example:

FROM t1
JOIN t2 on t1.ID = t2.ID

means show only records where the same ID value exists in both tables.

LEFT JOIN is same as LEFT OUTER JOIN and means to show all records from left table (i.e. the one that precedes in SQL statement) regardless of the existance of matching records in the right table.

RIGHT JOIN is same as RIGHT OUTER JOIN and means opposite of LEFT JOIN, i.e. shows all records from the second (right) table and only matching records from first (left) table.

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LEFT JOIN includes every row on the left, NULL filling the right as needed. RIGHT JOIN is the opposite.