postgresql SQL中两列的平均值
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Average of two columns in SQL
提问by AKIWEB
I wanted to take average of two columns and display in a new column something like this:
我想取两列的平均值并在一个新列中显示如下：
+-+--+--+--+--------+--------+
|A|B |C |D |AVG(B/C)|AVG(C/B)|
+-+--+--+--+--------+--------+
|S|23|34|56| | |
+-+--+--+--+--------+--------+
|T|45|6 |79| | |
+-+--+--+--+--------+--------+
So, as shown above, I needed to take the each row values and perform B/C and then take the average accordingly to display it in a new column.
因此，如上所示，我需要取每行值并执行 B/C，然后相应地取平均值以将其显示在新列中。
I wanted to do this in SQL query. Is it possible to perform this in a SQL command? I know the AVG()function does take the average of a column but how can I do B/Cand then take the average? also if I need to take the average of B and C as well how can i do that.
我想在 SQL 查询中做到这一点。是否可以在 SQL 命令中执行此操作？我知道该AVG()函数确实取了一列的平均值，但我该怎么做B/C然后取平均值？另外，如果我还需要取 B 和 C 的平均值，我该怎么做。
This is what I am doing right now:
这就是我现在正在做的事情：
Select A,B,C,D FROM tableTest where A='S';
I now have to take the average of corresponding and also have another two columns additionally in the query to show the respective results.
我现在必须取相应的平均值，并且在查询中还有另外两列以显示相应的结果。
采纳答案by MarcinJuraszek
You should give it a try:
你应该试一试：
SELECT A, AVG((B+C)/2) as bc, AVG((C+B)/2) as cb
FROM tableTest
WHERE A = 'S'
GROUP BY A
