问题
In my table one of column i have a value like below
Y-1
Y-2
Y-3
Y-4
Y-5
Y-6
Y-7
Y-8
Y-9
Y-10
Y-11
Y-12
Y-13
Y-14
when i am order by this column its working fine if the row has value up to Y-9 other wise my result is wrong like below.
Y-1
Y-10
Y-11
Y-12
Y-13
Y-14
Y-2
Y-3
Y-4
Y-5
Y-6
Y-7
Y-8
Y-9
But i want the output like below
Y-1
Y-2
Y-3
Y-4
Y-5
Y-6
Y-7
Y-8
Y-9
Y-10
Y-11
Y-12
Y-13
Y-14
How to acheive the above result.i am using oracle database.Any help will be greatly appreciated!!!!!
回答1:
You can use an order by manipulatinng the column content and cast to number eg:
order by substr(col1, 1,2), TO_NUMBER(sustr(col1, 3,10))
回答2:
Assuming the data is in a table t with a column col and the structure is an alphabetical string followed by dash followed by a number, and both the alphabetical and the number are always not NULL, then:
select col from t
order by substr(col, 1, instr(col, '-')), to_number(substr(col, instr(col, '-')+1))
回答3:
I think the good way is to get constant length field
select col from t
order by substr(col, 1, 2)|| lpad(substr(col, 3),5,'0')
it will correct work only with two nondigit simbol in begining of string up to 99999 number
来源：https://stackoverflow.com/questions/40342049/how-to-use-order-by-in-alphanumeric-column-in-oracle