我有以下查询，并且子查询在左连接时产生奇怪的结果。以下是正在发生的事情（StoreID 1的行在连接表中返回所有null）以及我真正想要的内容：
TABLE A
StoreID unitsales1 unitsales2 unitsales3
1 NULL NULL 6
2 12 12 12
3 12 NULL 12
TABLE B
StoreID prevunitsales1 prevunitsales2 prevunitsales3
2 NULL NULL 6
3 12 12 12
我得到的是什么
LEFT JOIN ON A.StoreId = B.StoreId
StoreID unitsales1 unitsales2 unitsales3 prevunitsales1 prevunitsales2 prevunitsales3
1 NULL NULL NULL NULL NULL NULL
2 12 12 12 NULL NULL 6
3 12 NULL 12 12 12 12
我想要什么
LEFT JOIN ON A.StoreId = B.StoreId
StoreID unitsales1 unitsales2 unitsales3 prevunitsales1 prevunitsales2 prevunitsales3
1 NULL NULL 6 NULL NULL NULL
2 12 12 12 NULL NULL 6
3 12 NULL 12 12 12 12
以下是查询：
SELECT SQL_CALC_FOUND_ROWS @storeid:=z.id,z.biz_name, z.wf_store_name, z.e_address, z.e_city, z.e_state, z.e_postal, IFNULL(total_sales - prev_total_sales,'CV') as diff_total_sales, IFNULL(d_source,'N/A') as d_source, IFNULL(unit_sales1 - prev_unit_sales1,(SELECT IFNULL(max(datetimesql),'NS') FROM storeCheckRecords WHERE store_id=@storeid AND upc=855555000019)) as diff_unit_sales1, IFNULL(unit_sales2 - prev_unit_sales2,(SELECT IFNULL(max(datetimesql),'NS') FROM storeCheckRecords WHERE store_id=@storeid AND upc=855555000022)) as diff_unit_sales2, IFNULL(unit_sales3 - prev_unit_sales3,(SELECT IFNULL(max(datetimesql),'NS') FROM storeCheckRecords WHERE store_id=@storeid AND upc=855555000025)) as diff_unit_sales3, IFNULL(unit_sales4 - prev_unit_sales4,(SELECT IFNULL(max(datetimesql),'NS') FROM storeCheckRecords WHERE store_id=@storeid AND upc=855555000028)) as diff_unit_sales4 FROM
(SELECT s1.id,s1.biz_name as biz_name, s1.wf_store_name as wf_store_name, s1.e_address as e_address,s1.e_city as e_city,s1.e_state as e_state,s1.e_postal as e_postal,sum(s2.unit_sales) as total_sales, sum(s2.unit_sales/4.28571428571) as week_avg,group_concat(DISTINCT s2.d_source separator ',') as d_source,
SUM(CASE u.id WHEN 1 THEN s2.unit_sales ELSE NULL END) AS unit_sales1,SUM(CASE u.id WHEN 2 THEN s2.unit_sales ELSE NULL END) AS unit_sales2,SUM(CASE u.id WHEN 3 THEN s2.unit_sales ELSE NULL END) AS unit_sales3,SUM(CASE u.id WHEN 4 THEN s2.unit_sales ELSE NULL END) AS unit_sales4
FROM allStores as s1
INNER JOIN storeCheckRecords AS s2
ON s1.id = s2.store_id
AND s2.datetimesql BETWEEN '2015-07-01' AND '2015-07-31'
AND s1.key_retailer LIKE 'FRESH THYME'
INNER JOIN ( SELECT 1 AS id, '855555000019' AS upc UNION SELECT 2, '855555000022' UNION SELECT 3, '855555000025' UNION SELECT 4, '855555000028' ) u ON u.upc = s2.upc
GROUP BY
s1.id) x
LEFT OUTER JOIN
(SELECT s1.id,s1.biz_name as prev_biz_name, s1.wf_store_name as prev_wf_store_name, s1.e_address as prev_e_address,s1.e_city as prev_e_city,s1.e_state as prev_e_state,s1.e_postal as prev_e_postal,sum(s2.unit_sales) as prev_total_sales, sum(s2.unit_sales/4.28571428571) as prev_week_avg,group_concat(DISTINCT s2.d_source separator ',') as prev_d_source,
SUM(CASE u.id WHEN 1 THEN s2.unit_sales ELSE 0 END) AS prev_unit_sales1,SUM(CASE u.id WHEN 2 THEN s2.unit_sales ELSE 0 END) AS prev_unit_sales2,SUM(CASE u.id WHEN 3 THEN s2.unit_sales ELSE 0 END) AS prev_unit_sales3,SUM(CASE u.id WHEN 4 THEN s2.unit_sales ELSE 0 END) AS prev_unit_sales4
FROM allStores as s1
INNER JOIN storeCheckRecords AS s2
ON s1.id = s2.store_id
AND s2.datetimesql BETWEEN '2015-06-01' AND '2015-06-30'
AND s1.key_retailer LIKE 'FRESH THYME'
INNER JOIN ( SELECT 1 AS id, '855555000019' AS upc UNION SELECT 2, '855555000022' UNION SELECT 3, '855555000025' UNION SELECT 4, '855555000028' ) u ON u.upc = s2.upc
GROUP BY
s1.id) y
ON x.id = y.id
RIGHT JOIN
(SELECT s1.id,s1.biz_name,s1.wf_store_name,s1.e_address,s1.e_city,s1.e_state,s1.e_postal
FROM allStores as s1
WHERE 1
AND s1.key_retailer LIKE 'FRESH THYME') z
ON y.id = z.id
ORDER BY biz_name ASC
LIMIT 0, 1000
我错过了什么？