Index usage
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Thread: Index usage

  1. #1

    Wink

    We have a table with 5 columns in the index. In the where clause, only the first column of index appears, I want to know why it doesn't use the index but full-scan instead.
    Thanks.

    Queyon
    Queyon Zeng

  2. #2
    Join Date
    Jan 2001
    Posts
    3,131

    Question

    When was the table last analyzed?
    What is the SQL in the query?
    What is the capitol of Malaysia?

    MH
    I remember when this place was cool.

  3. #3

    Wink SQL Query

    I have table (C1, C2, C3, C4, C5, C6, C7) with primary key (C1, C2, C3, C4, C5) using index and,
    SELECT * FROM table WHERE C1 = 10;
    It performs a full table scan even I just analyzed the table and index.
    Malaysia.
    Thanks.

    Queyon
    Queyon Zeng

  4. #4
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,447
    index low selectivity

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