[英]Combining sql inner and outer joins over multiple columns
我在如何在sql的select语句中联接以下表的语法上遇到问题。 关系如下:表a具有与b和d的内部联接。 表b也具有c的内部联接。 表e使用来自b和d的字段向a,b,c,d左连接。
这是代码。 重要的部分在底部。 其余只是表中的字段和计算所得的字段。 它似乎几乎可以工作,因为它可以检索数据。 但是有一点不太正确,因为在删除Futures_Orders行时基础就是删除Broker_Commissions行。请记住,在Futures_Orders上没有任何其他表设置删除级联。
SELECT "Futures_Orders"."Date"
,"Futures_Orders"."Symbol"
,"Futures_Orders"."Contract_Mth"
,"Futures_Orders"."Send_To_Broker"
,"Futures_Orders"."Order-Id"
,"Futures_Orders"."Broker"
,"Futures_Orders"."Order_Action"
,"Futures_Orders"."No_Contracts"
,"Futures_Orders"."Order_Price"
,"Futures_Orders"."Trade_Type"
,CASE "Futures_Orders"."Order_Action"
WHEN 'b'
THEN 's'
ELSE 'b'
END "If_Done_Action"
,"Futures_Orders"."If_Done_Price"
,"Futures_Orders"."No_Contracts" * (
CASE "Contract_Details"."USIntRates"
WHEN 'n'
THEN ABS("Futures_Orders"."Order_Price" - "Futures_Orders"."If_Done_Price") / "Contract_Details"."MinTick"
ELSE ABS(ABS(TRUNCATE (
"Futures_Orders"."Order_Price"
,0
) - TRUNCATE (
"Futures_Orders"."If_Done_Price"
,0
)) * "Contract_Details"."MinTick" - CASE
WHEN "Contract_Details"."Symbol" IN (
'FV'
,'TU'
)
THEN 400
ELSE 200
END * ABS("Futures_Orders"."Order_Price" - TRUNCATE (
"Futures_Orders"."Order_Price"
,0
) - "Futures_Orders"."If_Done_Price" + TRUNCATE (
"Futures_Orders"."If_Done_Price"
,0
)))
END * "Contract_Details"."MinTickVal" / "FX_Rates"."Rate" + CASE
WHEN "Broker_Commissions"."Commission" IS NULL
OR "Broker_Commissions"."Commission_AUD" + "Broker_Commissions"."Commission" = 0
THEN "Broker"."Commission"
ELSE "Broker_Commissions"."Commission_AUD" + "Broker_Commissions"."Commission" / "FX_Rates"."Rate"
END * 2
) "Risk"
,"Futures_Orders"."Trade_Reason"
,"Contract_Details"."MinTick"
,"Contract_Details"."MinTickVal"
,"Contract_Details"."Symbol"
,"Contract_Details"."Currency"
,"FX_Rates"."Code"
,"Broker"."Broker"
,"Broker_Commissions"."Symbol"
,"Broker_Commissions"."Broker"
,"Broker_Commissions"."ID"
FROM "Futures_Orders"
,"Contract_Details"
,"Broker"
,"FX_Rates"
LEFT JOIN "Broker_Commissions" ON "Broker_Commissions"."Broker" = "Broker"."Broker"
AND "Broker_Commissions"."Symbol" = "Contract_Details"."Symbol"
WHERE "Contract_Details"."Symbol" = "Futures_Orders"."Symbol"
AND "Broker"."Broker" = "Futures_Orders"."Broker"
AND "FX_Rates"."Code" = "Contract_Details"."Currency"
我认为您需要与此类似的东西。
每个<field>
不同,但是您没有提供
SELECT
FROM a
INNER JOIN b
ON a.<field> = b.<field>
INNER JOIN d
ON a.<field> = d.<field>
INNER JOIN c
ON b.<field> = c.<field>
LEFT JOIN e
ON e.<field> = b.<field>
AND e.<field> = d.<field>
假设您要联接的列在两个表中都被命名为相同的名称(并且没有重复引起歧义),我们可以使用NATURAL来简化语法。
d NATURAL LEFT JOIN (a NATURAL JOIN (b NATURAL JOIN c) NATURAL JOIN d)
您可以使用JOIN X ON (COLA = COLB)
语法替换NATURAL ... JOIN X
您的实际示例有所不同,可以这样写:
FROM "Futures_Orders" NATURAL JOIN "Contract_Details"
NATURAL JOIN "Broker"
INNER JOIN "FX_Rates" ON ("FX_Rates"."Code" = "Contract_Details"."Currency")
NATURAL LEFT JOIN "Broker_Commissions"
如果您使用NATURAL Join,则必须在查询中引用具有相同名称的列,而不必使用其表名。
您提到了Base(OpenOffice或LibreOffice),它具有自己的预处理器和语法差异,可以修改查询,有时甚至是错误地。
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