Re: What is meaning of "func" in "ref" column of EXPLAIN plan

[Rick James]

`createdate` varchar(8) DEFAULT NULL,
`createtime` varchar(8) DEFAULT NULL,
Recommend having a single column of type DATETIME or TIMESTAMP.

int(2) is still a 32-bit integer; the (2) means virtually nothing. Consider TINYINT.

Prefix indexes are virtually useless:
KEY `ship_name_idx` (`Ship_LastName`(24),`Ship_FirstName`(8)),

There is no advantage for (10) in this case:
KEY `phone_idx` (`Phone`(10)),

Reversing the fields in
KEY `datetype_idx` (`created`,`type`)
would help with
AND (AccountsReceivable.created BETWEEN '20071004' AND '20071011')
AND (AccountsReceivable.type ="CHARGE")