d*******n
发帖数: 524 | 1 We have a table (T_1) with e.g. 4 columns
T_1:
x y x z
1 2 3 4
3 6 1 -1
6 3 2 0
5 3 2 -10
I need a query to find out in each row which column has the max absolute value.
That is, I need to get the following table as output:
max_col
z
y
x
z
How to write this query in Oracle?
Thanks | a9
发帖数: 21638 | 2 有个旋转的关键字
sqlserver里是pivot
value.
【在 d*******n 的大作中提到】
: We have a table (T_1) with e.g. 4 columns
: T_1:
: x y x z
: 1 2 3 4
: 3 6 1 -1
: 6 3 2 0
: 5 3 2 -10
: I need a query to find out in each row which column has the max absolute value.
: That is, I need to get the following table as output:
: max_col
| B*****g
发帖数: 34098 | 3 homework？suppose the 3rd cloumn x should be x1, suppose no dup max value in
a row
SELECT CASE GREATEST (ABS(x), ABS(y), ABS(x1), ABS(z))
WHEN ABS(x) THEN 'x'
WHEN ABS(y) THEN 'y'
WHEN ABS(x1) THEN 'x1'
ELSE 'z'
END CASE
FROM t_1
value.
【在 d*******n 的大作中提到】
: We have a table (T_1) with e.g. 4 columns
: T_1:
: x y x z
: 1 2 3 4
: 3 6 1 -1
: 6 3 2 0
: 5 3 2 -10
: I need a query to find out in each row which column has the max absolute value.
: That is, I need to get the following table as output:
: max_col
| d*******n
发帖数: 524 | 4 Perfect! Thanks a lot!
Not for homework but work.
in
【在 B*****g 的大作中提到】
: homework？suppose the 3rd cloumn x should be x1, suppose no dup max value in
: a row
: SELECT CASE GREATEST (ABS(x), ABS(y), ABS(x1), ABS(z))
: WHEN ABS(x) THEN 'x'
: WHEN ABS(y) THEN 'y'
: WHEN ABS(x1) THEN 'x1'
: ELSE 'z'
: END CASE
: FROM t_1
:
| d*******n
发帖数: 524 | 5 One more question. Is this exactly same as
SELECT
DECODE(GREATEST (ABS(x), ABS(y), ABS(x1), ABS(z)), ABS(x), 'x',
ABS(y), 'y',
ABS(x1), 'x1',
'z')
FROM
【在 B*****g 的大作中提到】
: homework？suppose the 3rd cloumn x should be x1, suppose no dup max value in
: a row
: SELECT CASE GREATEST (ABS(x), ABS(y), ABS(x1), ABS(z))
: WHEN ABS(x) THEN 'x'
: WHEN ABS(y) THEN 'y'
: WHEN ABS(x1) THEN 'x1'
: ELSE 'z'
: END CASE
: FROM t_1
:
| B*****g
发帖数: 34098 | 6 same.
value
【在 d*******n 的大作中提到】
: One more question. Is this exactly same as
: SELECT
: DECODE(GREATEST (ABS(x), ABS(y), ABS(x1), ABS(z)), ABS(x), 'x',
:
: ABS(y), 'y',
:
: ABS(x1), 'x1',
:
: 'z')
: FROM
|
|
