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Sarangadhar
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Joined: 14 Oct 2004
Posts: 130
Topics: 43
Location: virtual village

Posted: Fri Nov 30, 2007 7:30 pm Post subject: access type

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I did EXPLAIN on below query: columns of the tables are A thru Z.

Code:

SELECT * FROM
TAB2 JOIN TAB1
ON TAB2.A = TAB1.A
AND TAB2.B = TAB1.B
AND TAB2.C = TAB1.C
AND TAB2.D = TAB1.D
AND TAB2.E = TAB1.E
AND TAB2.F = TAB1.F

WHERE TAB2.A = 1
AND TAB2.D = 2
AND TAB2.M = 3
AND TAB1.L = 4
;

AN INDEX IS AVAILABLE ON TAB1(A,B,C,D,E,F)
AN INDEX IS AVAILABLE ON TAB2(A,B,C,D,E,F,G)

Result of EXPLAIN:
tab2:
access type I
matching columns 5

tab1:
access type R

Question: why the TAB1 access type is table space scan (R)/ since I have the index on the TAB1, I believe I should at least get the access type=I with matching columns 1.
_________________
Thanks

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Sarangadhar
Beginner

Joined: 14 Oct 2004
Posts: 130
Topics: 43
Location: virtual village

Posted: Fri Nov 30, 2007 7:31 pm Post subject:

sorry, I misgave the EXPLAIN results: tab2: access type I matching columns 6 tab1: access type R matching columns 0 _________________ Thanks

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