----- Original Message -----
From: "Jonathan Mangin" <[EMAIL PROTECTED]>
To: <mysql@lists.mysql.com>
Sent: Monday, November 21, 2005 8:48 AM
Subject: Index of JOINed table?
I have a simple query, (part of a union).
calendar is a table of only dates, `date` as PK.
sales has a multi-col index on (date, uid).
(select calendar.date as date,
time_format(time(sales.date),'%H:%i') as time,
from calendar
left join sales
on date(sales.date) = calendar.date
and sales.uid = 'george'
where calendar.date between '2005-08-01' and '2005-08-14')
First, I don't quite understand joins(!) on constants (sales.uid =
'george').
Is this proper, or should uid be included in where clause?
Second, explain shows no possible keys for sales.
id select_type table type possible_keys key key_len
ref rows Extra
1 PRIMARY calendar range PRIMARY PRIMARY 3 NULL 11
Using where; Using index
1 PRIMARY sales ALL NULL NULL NULL NULL 23
I guess I found the problem...
on date(sales.date) = calendar.date
If I create separate date and time columns it lists, and uses,
possible_keys.
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