SQL query group by and select the maximum absolute value - sql

Question

"Table1" structure is as shown below:
source table table1
Player_NAME || Player_NUMBER || Client_name || Client_country || Player_country|| Rating
GERALD || A1234 || BENFIELD || IND || IND || 76
GERALD ||A6578 || ROTFIELD || USA || USA || 64
KUMAR || P1234 || LFV || ARG || ARG || -24
KUMAR || P5678 ||JEURASIN || ARG || TUR ||-32
KUMAR || P0101 ||ARGENIA ||ARG ||POL ||-16
ANDREW ||R1234 || GENMAD || GER || GER || 23
I need to select the records from above table “Table1” and copy them to “Table2”.
I need to select the player record from table1 which satisfy the below conditions :
If a player has multiple client_names or multiple client_country, then select the record which has the maximum value of rating . If it is negavie, then take the absolute value of that value. i.e if the rating is -10 and -34, then take the absolute value which is greatest. i. e by taking absolute value it is 10,34 and 34 is greatest one.
For ex: Kumar has 3 diff client names or 3 diff client_country ,so for kumar the record with rating 32 should be selected ,after taking the absolute value of it.
Below is the expected output:
Player_NAME || Player_NUMBER ||Client_name || Client_country ||Player_country|| Rating
GERALD || A1234 || BENFIELD|| IND|| IND|| 76
KUMAR || P5678 || JEURASIN ||ARG ||TUR || -32
ANDREW || R1234 || GENMAD ||GER ||GER || 23
destination table-'table2'

Answer 1

You can try something like this:
INSERT INTO Table2
(
Player_Name,
Player_Number,
Cliet_Name,
Client_country,
Player_country,
Rating
)
SELECT
Player_Name,
Player_Number,
Cliet_Name,
Client_country,
Player_country,
MAX(ABS(Rating)) OVER (PARTITION BY player_Name ORDER BY Cliet_Name,
Client_country) as Rating
FROM
table1

Answer 2

If your DBMS supports Analytical Function you can utilize ROW_NUMBER:
select ... -- all columns but rn
from
(
select ... -- all columns
,row_number()
over (partition by player_name
order by abs(Rating) desc as rn
from table1
) as dt
where rn = 1;
Otherwise use a Correlated Subquery:
select *
from table1 as t1
where abs(rating) =
( select max(abs(rating))
from table1 as t2
where t1.player_name = t2.player_name
)
If you got multiple rows with the same max(abs(rating)) #1. will select one of them randomly, but #2 will select all.

Answer 3

I guess, this query will work:
select
max(abs(Rating))
from Table1
group by Player_NAME
To insert data into Table2, you can do it like so:
INSERT INTO Table2 (
Player_Name,
Player_Number,
Cliet_Name,
Client_country,
Player_country,
Rating
)
SELECT
t1.Player_Name,
t1.Player_Number,
t1.Cliet_Name,
t1.Client_country,
t1.Player_country,
t1.Rating
FROM Table1 t1
INNER JOIN (
SELECT
Player_NAME,
MAX(ABS(Rating)) as Rating
FROM Table1
GROUP BY Player_NAME
) t2 ON t2.Player_NAME = t1.Player_NAME AND ABS(t1.Rating) = t2.Rating