Question

I have following table structure.

town:

id (MEDINT,PRIMARY KEY,autoincrement), 
town(VARCHAR(150),not null),
lat(FLOAT(10,6),notnull)
lng(FLOAT(10,6),notnull)

i frequently use “SELECT * FROM town ORDER BY town” query. I tried indexing town but it is not being used. So what is the best way to index so that i can speed up my queries.

USING EXPLAIN(UNIQUE INDEX Is PRESENT ON town):

 mysql> EXPLAIN SELECT * FROM studpoint_town order by town \G
*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: studpoint_town
         type: ALL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: 3
    Extra: Using filesort

1 row in set (0.00 sec)

ragards ,
ravi.

Answer 1

Your EXPLAIN output indicates that currently the studpoint_town table has only 3 rows. As explained in the manual:

The output from EXPLAIN shows ALL in the type column when MySQL uses a table scan to resolve a query. This usually happens under the following conditions:

[…]

• The table is so small that it is faster to perform a table scan than to bother with a key lookup. This is common for tables with fewer than 10 rows and a short row length. Don’t worry in this case.