Improving/ Optimizing Performance Query in PHP, MySQL,Zend - php

Question

I have a invoices, invoices_items, order, order_items. Invoices and Orders tables contains around 1 Millions records. Invoices_items and Orders_items tables contains more than 2 Millions records. Items table contains 2 Hundred Thousands records. Now I want to generate a report based on my filter like customers, item categories and more....
Please refer queries.
Running on PHP 5.6. MySql 5.7 and Apache2.
SELECT
`si_items`.`item_id`
, SUM(qty) AS `qty`
, IFNULL(SUM(selling_price * (qty)), 0) AS `salestotal`
, GROUP_CONCAT(si.id) AS `siso_id`
, MAX(si.date_transaction) AS `date_transaction`
FROM
`invoice_items` AS `si_items`
LEFT JOIN `invoice` AS `si`
ON si.id = si_items.parent_id
LEFT JOIN `items`
ON si_items.item_id = items.id
WHERE (
DATE_FORMAT(si.date_transaction, '%Y-%m-%d') BETWEEN '2019-01-01'
AND '2019-02-15'
)
AND (si.approved = 1)
AND (si.deleted = 0)
AND (items.deleted = 0)
GROUP BY `item_id`
UNION
SELECT
`so_items`.`item_id`
, SUM(qty) AS `qty`
, IFNULL(SUM(selling_price * (qty)), 0) AS `salestotal`
, GROUP_CONCAT(so.id) AS `soso_id`
, MAX(so.date_transaction) AS `date_transaction`
FROM
`order_items` AS `so_items`
LEFT JOIN `order` AS `so`
ON so.id = so_items.parent_id
LEFT JOIN `items`
ON so_items.item_id = items.id
WHERE (
DATE_FORMAT(so.date_transaction, '%Y-%m-%d') BETWEEN '2019-01-01'
AND '2019-02-15'
)
AND (so.approved = 1)
AND (so.deleted = 0)
AND (items.deleted = 0)
GROUP BY `item_id`
When I executed this query for 50 days. It took 1 minute 20 seconds to execute this query.
INDEXES are added in tables
Invoice & Order Tables
PRIMARY KEY (`id`),
KEY `account_id` (`account_id`),
KEY `approved` (`approved`),
KEY `deleted` (`deleted`),
KEY `finalised` (`finalised`),
KEY `rp_status` (`rp_status`),
KEY `sales_types_id` (`sales_types_id`),
KEY `account_type_id` (`account_type_id`),
KEY `company_id` (`company_id`),
KEY `date_transaction` (`date_transaction`)
Invoices_items & Order_items
PRIMARY KEY (`id`),
KEY `deleted` (`deleted`),
KEY `item_id` (`item_id`),
KEY `parent_id` (`parent_id`),
KEY `vat_id` (`vat_id`),
KEY `qty` (`qty`),
Explain Query
Explain Query
I need to increase performance of this query. Could you please guide me how to proceed?
Show Create Tables
CREATE TABLE `invoice` (
`id` char(36) NOT NULL,
`reference` varchar(25) DEFAULT NULL,
`company_id` char(36) DEFAULT NULL,
`branch_id` char(36) DEFAULT NULL,
`account_id` char(36) DEFAULT NULL,
`contact_id` char(36) DEFAULT NULL,
`transaction_type` varchar(10) DEFAULT NULL,
`sales_types_id` int(11) DEFAULT '0',
`quote_validity` int(11) DEFAULT '0',
`delivery_method_id` int(11) DEFAULT '0',
`sales_representative_id` int(11) DEFAULT '0',
`account_type_id` char(36) DEFAULT NULL,
`vat_exempted` tinyint(1) DEFAULT '0',
`description` text,
`finalised` tinyint(1) DEFAULT '0' COMMENT 'Not Yet finalised - status=1; Need Approval - status = 2; Approved - status = 3',
`approved` tinyint(1) DEFAULT '0',
`approved_user_id` int(11) DEFAULT '0',
`default_sales_location_id` char(36) DEFAULT NULL COMMENT '0-Yes; 1-No',
`generate_do` tinyint(1) DEFAULT '1',
`generate_dn` tinyint(4) DEFAULT '1',
`do_status` tinyint(1) DEFAULT '0',
`cn_status` tinyint(1) DEFAULT '0',
`rp_status` tinyint(1) DEFAULT '0',
`dm_status` tinyint(1) DEFAULT '0',
`currency_id` char(36),
`exchange_rate_id` tinyint(1) DEFAULT '0',
`exchange_rate` double DEFAULT '1',
`date_transaction` datetime DEFAULT NULL,
`date_created` datetime DEFAULT NULL,
`date_modified` datetime DEFAULT NULL,
`created_user_id` int(11) DEFAULT '0',
`modified_user_id` int(11) DEFAULT '0',
`deleted` tinyint(1) DEFAULT '0',
PRIMARY KEY (`id`),
KEY `account_id` (`account_id`),
KEY `approved` (`approved`),
KEY `branch_id` (`branch_id`),
KEY `cn_status` (`cn_status`),
KEY `created_user_id` (`created_user_id`),
KEY `date_created` (`date_created`),
KEY `deleted` (`deleted`),
KEY `do_status` (`do_status`),
KEY `finalised` (`finalised`),
KEY `reference` (`reference`),
KEY `rp_status` (`rp_status`),
KEY `sales_types_id` (`sales_types_id`),
KEY `account_type_id` (`account_type_id`),
KEY `company_id` (`company_id`),
KEY `date_transaction` (`date_transaction`),
KEY `default_sales_location_id` (`default_sales_location_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
CREATE TABLE `invoice_items` (
`id` char(36) NOT NULL,
`parent_id` char(36) DEFAULT NULL,
`item_id` char(36) DEFAULT NULL,
`qty` double DEFAULT '0',
`cost_price` double DEFAULT '0',
`list_price` double DEFAULT '0',
`selling_price` double DEFAULT '0',
`unit_price` double DEFAULT '0',
`vat` double DEFAULT '0',
`amount` double DEFAULT '0',
`special_discount` double DEFAULT '0',
`price_change_status` tinyint(1) DEFAULT '0',
`remarks` text,
`vat_id` int(11) DEFAULT '1',
`stock_category_id` tinyint(2) DEFAULT '0' COMMENT '1: Stockable 2: Service',
`is_giftitem` tinyint(1) DEFAULT '0' COMMENT '1: Gift Item 0: NO Gift',
`item_type_status` tinyint(1) DEFAULT '0',
`date_created` datetime DEFAULT NULL,
`date_modified` datetime DEFAULT NULL,
`created_user_id` int(11) DEFAULT '0',
`modified_user_id` int(11) DEFAULT '0',
`deleted` tinyint(1) DEFAULT '0',
PRIMARY KEY (`id`),
KEY `deleted` (`deleted`),
KEY `item_id` (`item_id`),
KEY `parent_id` (`parent_id`),
KEY `stock_category_id` (`stock_category_id`),
KEY `item_type_status` (`item_type_status`),
KEY `vat_id` (`vat_id`),
KEY `amount` (`amount`),
KEY `qty` (`qty`),
KEY `unit_price` (`unit_price`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8

Answer 1

Don't use LEFT JOIN when you mean JOIN. In particular, for joining to si.
WHERE (
DATE_FORMAT(si.date_transaction, '%Y-%m-%d') BETWEEN '2019-01-01'
AND '2019-02-15'
)
-->
WHERE si.date_transaction >= '2019-01-01'
AND si.date_transaction < '2019-01-15'
so that an index (see below) can use that column
WHERE si.date_transaction ...
AND (si.approved = 1)
AND (si.deleted = 0)
Add a composite index:
INDEX(deleted, approved, -- in either order
date_transaction) -- last
Make similar changes to so. Then let's hear how the performance is and see what the EXPLAIN has changed to.
UUIDs
Beware of UUIDs, they are bulky and slow. They are especially slow if the entire table cannot be cached.
I suspect you have uuids because I see CHAR(36).
By having CHARACTER SET utf8, that means 108 bytes is being used!. A UUID can be packed into a 16-byte BINARY(16). This would help with space (and hence speed).
But the real problem with UUIDs is with the randomness. Once the table becomes huge, the system becomes I/O-bound since the 'next' UUID is unlikely to be cached.
Consider switching to AUTO_INCREMENT ids. This is much preferred for single-server systems. If you need to generate ids from multiple locations, you may still need UUIDs.
More on UUIDs.