SQL 将 2 个不同表中的 2 个值相乘
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Multiply 2 values from 2 different tables
提问by user752160
I'm trying to multiply value X by value Y with SQL. Value X is located in table A and B is located in table B. I couldn't find the answer for this.
我正在尝试使用 SQL 将值 X 乘以值 Y。值 X 位于表 A 中，B 位于表 B 中。我找不到答案。
Table Transactions
表事务
ID Transaction_ID Total_Amount
1 001 1200
2 002 1500
3 003 1600
Table Rates
表费率
ID Currency_Name Exchange_Rate
1 AUD 1.5
2 SEK 2.0
3 PLN 3.0
The question I'm trying to answer is:
我试图回答的问题是：
What is the Total_Amount for transaction 001 in SEK (Swedish Crown). So I need to multiply 1200 * 2.0 and display the result.
SEK（瑞典克朗）中交易 001 的 Total_Amount 是多少。所以我需要乘以 1200 * 2.0 并显示结果。
回答by TBohnen.jnr
Edited based on added info
根据添加的信息进行编辑
SELECT Total_Amount * Exchange_Rate AS Value
FROM Transactions, Rates
WHERE Rates.Currency_Name = 'Sek' and Transaction_id = 001
回答by garnertb
To answer your question:
回答你的问题：
What is the Total_Amount for transaction 001 in SEK (Swedish Crown). So I need to multiply 1200 * 2.0 and display the result.
SEK（瑞典克朗）中交易 001 的 Total_Amount 是多少。所以我需要乘以 1200 * 2.0 并显示结果。
Use:
用：
SELECT ID, Transaction_ID, Total_Amount, Total_Amount*(SELECT Exchange_Rate from Rates where Currency_Name='SEK')
FROM TRANSACTIONS
WHERE TRANSACTION_ID='001'
回答by Harry Joy
how about this:
这个怎么样：
select a.x*b.y from tableA a, tableB b
回答by krtek
This should work, depending on your table structure :
这应该有效，具体取决于您的表结构：
select table1.x * table2.y
from table1, table2;
But I actually doubt that this is really what you want to do, if you provide more information, we could give you a much better answer. Please provide table structure and you're real goal !
但我实际上怀疑这是否真的是您想要做的，如果您提供更多信息，我们可以为您提供更好的答案。请提供表格结构，您才是真正的目标！
