计算平均值后，在同一个表中合并两行

Question

I have data in my table named prices as below;

+--------------------------------------+-------+-------+--------+------------+
| ID                                   | E5    | E10   | DIESEL | DATE       |
+--------------------------------------+-------+-------+--------+------------+
| a1978958-a6c4-447b-a90c-3d189da0f831 | 1.289 | 1.269 |  1.059 | 07/22/2017 |
| a1978958-a6c4-447b-a90c-3d189da0f831 | 1.259 | 1.239 |  1.029 | 07/22/2017 |
+--------------------------------------+-------+-------+--------+------------+

I want to calculate average values of E5, E10, DIESEL. Then I want to merge two columns with ID and DATE inside same table. (Column name and order will remain same)

select ID, DATE, avg(E5) as E5, avg(E10) as E10, avg(DIESEL) as DIESEL from prices group by ID, DATE;

Then I inserted the following query.

select t1.ID, t2.ID, t1.DATE, t2.DATE from prices as t1 inner join prices as t2 on t1.ID = t2.ID and t1.DATE = t2.DATE;

I couldn't achieve merging two rows with two above-mentioned queries. Result will be the following figure in all row values.

  +--------------------------------------+-------+-------+--------+------------+
    | ID                                   | E5    | E10   | DIESEL | DATE       |
    +--------------------------------------+-------+-------+--------+------------+
    | a1978958-a6c4-447b-a90c-3d189da0f831 | 1.274 | 1.254 |  1.044 | 07/22/2017 |
    +--------------------------------------+-------+-------+--------+------------+

Is there any idea how to do?

Thanks in advance,

Answer 1

is this the thing that you are looking for: kept the result on temp table, deleted the actual values, and inserted the avg values to the same table?

SELECT ID, avg(E5) as E5, avg(E10) as E10, avg(DIESEL) as DIESEL, DATE INTO #TEMP from prices group by ID, DATE
DELETE FROM prices
INSERT INTO prices SELECT * FROM #TEMP
DROP TABLE #TEMP

Answer 2

You seem to be asking for:

select ID, avg(E5) as E5, avg(E10) as E10, avg(DIESEL) as DIESEL
from prices
group by ID;

Does this do what you want?