This is mysql explain plan for one of the query I am looking into.
+----+-------------+--------+-------+---------------+---------+---------+------+------+-------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+--------+-------+---------------+---------+---------+------+------+-------+
| 1 | SIMPLE | table2 | index | NULL | PRIMARY | 4 | NULL | 6 | |
| 1 | SIMPLE | table3 | ALL | NULL | NULL | NULL | NULL | 23 | |
| 1 | SIMPLE | table1 | ALL | NULL | NULL | NULL | NULL | 8 | |
| 1 | SIMPLE | table5 | index | NULL | PRIMARY | 4 | NULL | 1 | |
+----+-------------+--------+-------+---------------+---------+---------+------+------+-------+
4 rows in set (0 sec)
What is the significance of the order of statements in this output ? Does it mean that table5 is read before all others ?
The tables are listed in the output in the order that MySQL would read them while processing the query. You can read more about the Explain plan output here.
Additionally, the output tells me:
type
column), which were primary keys (based on the key
column). The other two could not use any indexes.If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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