Join order..........

[sparrow]

hi guys,
Would the ordered of the joins make a difference on large tables i.e.
SELECT T1.*, T2.*, T3.* FROM T1
LEFT JOIN T2 ON T1.id = T2.id
LEFT JOIN T3 ON T1.id = T3.id
WHERE ......

be any different from
SELECT T1.*, T2.*, T3.* FROM T1
LEFT JOIN T3 ON T1.id = T3.id
LEFT JOIN T2 ON T1.id = T2.id
WHERE ......

and would the following make a difference as welljoin order

SELECT T1.*, T2.*, T3.* FROM T1
LEFT JOIN T2 ON T1.id = T2.id
LEFT JOIN T3 ON T2.id = T3.id
WHERE .....

Thanks in advance -- This message may have been cut off and the rest will only be shown to members. To become a member, click here --

[evy]

Ofcourse, it makes a difference depending on the relative sizes of the tables without indexes or on the number of matching rows in each table with indexes. -- This message may have been cut off and the rest will only be shown to members. To become a member, click here --