I'm trying to get the max and min date values in column C based on the (column A, column B) unique pair combinations.
Suppose I have a table like:
column_A column_B column_C
A 1 2019-08-11
A 1 2018-11-12
A 1 2017-11-12
A 11 2020-03-03
A 11 2021-01-10
A 11 2021-02-02
B 2 2020-11-11
B 2 2020-12-12
The output I want to get is:
column_A column_B column_C
A 1 2019-08-11
A 1 2017-11-12
A 11 2020-03-03
A 11 2021-02-02
B 2 2020-11-11
B 2 2020-12-12
My attempt query has been taking 20 mins to run with no output yet (just tried to get max date from column C for now):
SELECT column_A, column_B, column_C FROM table_name
WHERE column_C IN (
SELECT MAX(column_C) FROM table_name
GROUP BY column_A, column_B
)
Just use two conditions:
select t.*
from t
where column_c = (select max(t2.colc)
from table_name t2
where t2.column_A = t.column_A and t2.column_B = t.column_B
) or
column_c = (select min(t2.colc)
from table_name t2
where t2.column_A = t.column_A and t2.column_B = t.column_B
) ;
You can use two queries that group by column_a
and column_b
, one with the max and one with the min of column_c
, and then union all
them:
SELECT column_a, column_b, MAX(column_c)
FROM table_name
GROUP BY column_a, column_b
UNION ALL
SELECT column_a, column_b, MIN(column_c)
FROM table_name
GROUP BY column_a, column_b
you can create a temporary view and GROUP BY the desired columns
select column_a,column_b,max(column_c) as max_column_c
from (select column_a,column_b,column_c,to_char(column,'YYYY') as year
from table_t) aa
group by column_a,column_b,year
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