mysql派生表聯(lián)表查詢的方法是什么

本文講解"mysql派生表聯(lián)表查詢的方法是什么"，希望能夠解決相關(guān)問題。

前情提要：

公司運(yùn)營的一個(gè)商城系統(tǒng)，忽然發(fā)現(xiàn)訂單提現(xiàn)功能有問題，有大量的商戶體現(xiàn)金額和訂單金額不一致。于是產(chǎn)生了需求，需要把提現(xiàn)表和供應(yīng)商表作為一個(gè)結(jié)果集，連接上訂單表中的訂單金額，通過計(jì)算訂單表的金額和體現(xiàn)表商戶提現(xiàn)的金額進(jìn)行比對，查看商戶是多提現(xiàn)了還是少提現(xiàn)了。

下面記錄我的查詢過程。

查詢過程：

剛開始，第一步我以提現(xiàn)表為主表，查詢出來相關(guān)結(jié)果。mysql語句如下

select??count(ysw.supply_id)?as?'提現(xiàn)次數(shù)',ysw.user_id?as?'供應(yīng)商對應(yīng)的用戶id',?ysw.supply_id??as?'供應(yīng)商id'?,sum(ysw.money)??as?'供應(yīng)商提現(xiàn)總金額',
case?ysw.pay_type?when?10?then?'微信'?when?20?then?'支付寶'?else?'銀行卡'?end?as?'支付方式'?,
ys.supply_name?as?'供應(yīng)商名稱',ys.money?as?'供應(yīng)商余額',ys.freez_money?as?'供應(yīng)商凍結(jié)金額（已提現(xiàn)金額）'
from?yoshop_supply_withdraw?as?ysw?left?join?yoshop_supply?as?ys?on?ysw.supply_id?=?ys.supply_id
where?ysw.create_time?<?1647446400?and?ysw.apply_status?in?(10,20,40)?group?by?ysw.supply_id
order?by?sum(ysw.money)?desc?;

查詢結(jié)果如圖是正常的：

接下來，我在左鏈接上訂單表的數(shù)據(jù)，又添加一個(gè)了left join，金額相關(guān)數(shù)據(jù)發(fā)生了變化嚴(yán)重不一致,而且查詢時(shí)間明顯延長，mysql語句如下

select??count(ysw.supply_id)?as?'提現(xiàn)次數(shù)',ysw.user_id?as?'供應(yīng)商對應(yīng)的用戶id',?ysw.supply_id??as?'供應(yīng)商id'?,sum(ysw.money)??as?'供應(yīng)商提現(xiàn)總金額',
case?ysw.pay_type?when?10?then?'微信'?when?20?then?'支付寶'?else?'銀行卡'?end?as?'支付方式'?,
ys.supply_name?as?'供應(yīng)商名稱',ys.money?as?'供應(yīng)商余額',ys.freez_money?as?'供應(yīng)商凍結(jié)金額（已提現(xiàn)金額）',sum(yo.pay_price)

from?yoshop_supply_withdraw?as?ysw?left?join?yoshop_supply?as?ys?on?ysw.supply_id?=?ys.supply_id
left?join?yoshop_order?as?yo?on?yo.supply_ids?=ysw.supply_id?

where?ysw.create_time?<?1647446400?and?ysw.apply_status?in?(10,20,40)?group?by?ysw.supply_id
order?by?sum(ysw.money)?desc?;

查詢結(jié)果對比圖如下：

經(jīng)過實(shí)踐，我想直接通過左連接查詢到提現(xiàn)表金額和訂單表金額是行不通的。通過網(wǎng)上查資料，以及在技術(shù)群里請教，

優(yōu)化了思路： 把提現(xiàn)的統(tǒng)計(jì)好,把訂單的統(tǒng)計(jì)好， 最后兩個(gè)結(jié)果集再根據(jù)供應(yīng)商id做個(gè)鏈接

接下來就是，三步走了， 第一步：把提現(xiàn)的統(tǒng)計(jì)好，上面第一次嘗試的第一步就是了， 第二步：把訂單表的數(shù)據(jù)統(tǒng)計(jì)好。由于使用系統(tǒng)的原因，我直接使用的訂單商品表計(jì)算的訂單總金額，這一步也是分三步走的，我直接上代碼：

1.查詢yoshop_order所有進(jìn)行中，已完成的?訂單id(order_id);
	select?order_id?from?yoshop_order?where?order_status?in?(10,30);
	
2.查詢沒有退款的訂單id
	select?order_id?from?yoshop_order?where?order_status?in?(10,30)?and?order_id?not?in?(?select?order_id?from?yoshop_order_refund);
	
3.查詢訂單商品表中?所有的訂單金額

select??supply_id??as?'供應(yīng)商id'?,?sum(total_pay_price)??as?'供應(yīng)商訂單總金額'?from?yoshop_order_goods?where??create_time?<?1647446400?and?order_pay_status?=?0??and??order_id?in(select?order_id?from?yoshop_order?where?order_status?in?(10,30)?and?order_id?not?in?(?select?order_id?from?yoshop_order_refund)	?)??group?by?supply_id?
order?by?sum(total_pay_price)?desc?;

接下來就是進(jìn)行把第一步和第二步的查詢結(jié)果當(dāng)作派生表，進(jìn)行左連接查詢。我在這一步耗費(fèi)的時(shí)間和精力最多。如果你能認(rèn)真看完，相信一定會(huì)有收貨。我在這里把我錯(cuò)誤的過程也進(jìn)行了記錄 第一次錯(cuò)誤拼接：

select?*?from??(
	select??count(ysw.supply_id)?as?'提現(xiàn)次數(shù)',ysw.user_id?as?'供應(yīng)商對應(yīng)的用戶id',?ysw.supply_id??as?'supply_id'?,sum(ysw.money)??as?'供應(yīng)商提現(xiàn)總金額',
	case?ysw.pay_type?when?10?then?'微信'?when?20?then?'支付寶'?else?'銀行卡'?end?as?'支付方式'?,
	ys.supply_name?as?'供應(yīng)商名稱',ys.money?as?'供應(yīng)商余額',ys.freez_money?as?'供應(yīng)商凍結(jié)金額（已提現(xiàn)金額）'
	from?yoshop_supply_withdraw?as?ysw?left?join?yoshop_supply?as?ys?on?ysw.supply_id?=?ys.supply_id
	where?ysw.create_time?<?1647446400?and?ysw.apply_status?in?(10,20,40)?group?by?ysw.supply_id
	order?by?sum(ysw.money)?desc?)?as?t1?
union?all????//?left?join?,這里是注釋記得刪除

select?*?from???--??這里是錯(cuò)誤的不應(yīng)該在查詢
		(select??supply_id??as?'supply_id'?,?sum(total_pay_price)??as?total_pay_price?from?yoshop_order_goods?where??create_time?<?1647446400?and?order_pay_status?=?0??and??order_id?in(
	select?order_id?from?yoshop_order?where?order_status?in?(10,30)?and?order_id?not?in?(
	select?order_id?from?yoshop_order_refund)	?)??group?by?supply_id?
order?by?sum(total_pay_price)?desc?)?as?t2
								
on?t1.suppply_id?=?t2.suppply_id

通過這一次試錯(cuò)，明顯看出我把left join 和 union all 的含義記錯(cuò)了,并且在拼接的時(shí)候重復(fù)使用了select * from 。雖然是試錯(cuò)了，但也是有收貨的，接下來進(jìn)行了第二次錯(cuò)誤的拼接：

select?t1.提現(xiàn)次數(shù)?,t1.供應(yīng)商對應(yīng)的用戶id?,t1.supply_id,?t1.支付方式?,t1.供應(yīng)商名稱,t1.供應(yīng)商余額,?t1.供應(yīng)商凍結(jié)金額（已提現(xiàn)金額）,?t2.total_pay_price?from??(
select??count(ysw.supply_id)?as?'提現(xiàn)次數(shù)',ysw.user_id?as?'供應(yīng)商對應(yīng)的用戶id',?ysw.supply_id??as?supply_id?,sum(ysw.money)??as?'供應(yīng)商提現(xiàn)總金額',
case?ysw.pay_type?when?10?then?'微信'?when?20?then?'支付寶'?else?'銀行卡'?end?as?'支付方式'?,
	ys.supply_name?as?'供應(yīng)商名稱',ys.money?as?'供應(yīng)商余額',ys.freez_money?as?'供應(yīng)商凍結(jié)金額（已提現(xiàn)金額）'
	from?yoshop_supply_withdraw?as?ysw?left?join?yoshop_supply?as?ys?on?ysw.supply_id?=?ys.supply_id
	where?ysw.create_time?<?1647446400?and?ysw.apply_status?in?(10,20,40)?group?by?ysw.supply_id
	order?by?sum(ysw.money)?desc?)?as?t1?
????????
?left?join
		
(select??supply_id??as?supply_id?,?sum(total_pay_price)??as?total_pay_price?from?
yoshop_order_goods?where??create_time?<?1647446400?and?order_pay_status?=?0??
and??order_id?in(
select?order_id?from?yoshop_order?where?order_status?in?(10,30)?
and?order_id?not?in?(
select?order_id?from?yoshop_order_refund)	?)??
group?by?supply_id?
order?by?sum(total_pay_price)?desc?)?as?t2						
on?t1.suppply_id?=?t2.suppply_id

通過這兩次錯(cuò)誤的嘗試，以及根據(jù)嘗試過程中mysql給出的錯(cuò)誤提示，知道自己是在左連接上使用錯(cuò)誤了，應(yīng)該在開始查詢出來所有的字段，left join 后不能在使用select * 最后，回想了一遍自己所學(xué)的left join的語法，寫出了最后的正確的查詢結(jié)果

select?t1.supply_id?'供應(yīng)商id',t1.supply_name?'供應(yīng)商名稱',t1.user_id?'供應(yīng)商綁定的用戶id',t1.withdrawtime?'供應(yīng)商提現(xiàn)次數(shù)'?,t1.supplyallmoney?'供應(yīng)商提現(xiàn)金額',t1.payway?'供應(yīng)商提現(xiàn)方式',t1.supply_money?'供應(yīng)商賬戶余額',t1.supply_free_money?'供應(yīng)商凍結(jié)余額（已提現(xiàn)金額）',
t2.total_pay_price?'供應(yīng)商訂單總金額',t2.order_id?'供應(yīng)商訂單數(shù)量'
from??(											
select??count(ysw.supply_id)?as?withdrawtime,??ysw.user_id?as?user_id,???ysw.supply_id??as?supply_id?,??sum(ysw.money)??as?supplyallmoney,???ysw.alipay_name?as?alipay_name?,ysw.alipay_account?as?alipay_account,??ysw.audit_time?as?audit_time?,??ysw.bank_account?as?bank_account,???ysw.bank_card?as?bank_card,???ysw.bank_name?as?bank_name,
case?ysw.pay_type?when?10?then?'微信'?when?20?then?'支付寶'?else?'銀行卡'?end?as?payway?,
ys.supply_name?as?supply_name,??ys.money?as?supply_money,??ys.freez_money?as?supply_free_money
from?yoshop_supply_withdraw?as?ysw?left?join?yoshop_supply?as?ys?on?ysw.supply_id?=?ys.supply_id
where?ysw.create_time?<?1647446400?and?ysw.apply_status?in?(10,20,40)?group?by?ysw.supply_id
order?by?sum(ysw.money)?desc?)?as?t1?
	
?left?join

????(select??supply_id??as?'supply_id'?,?count(order_id)?as?order_id,???sum(total_pay_price)????as?total_pay_price?
????from?	yoshop_order_goods?where??create_time?<?1647446400?and?order_pay_status?=?0??
????and??order_id?in(
????????select?order_id?from?yoshop_order?where?order_status?in?(10,30)?
????and?order_id?not?in?(
????????select?order_id?from?yoshop_order_refund)	?)?
????group?by?supply_id?
????order?by?sum(total_pay_price)?desc?)?as?t2
								
on?t1.supply_id?=?t2.supply_id

正確的結(jié)果截圖：

關(guān)于 "mysql派生表聯(lián)表查詢的方法是什么" 就介紹到此。希望多多支持碩編程。