Custom Order in Oracle SQL

问题

I need to order transaction based on the currency. However I need to implement a custom order by, which makes the USD to always comes on the top, and the rest should be ordered asc.

for example :

should be sorted like :

Is there a simple way to handle this?

回答1:

Don't know if this qualifies as simple:

order by 
    case 
       when currency = 'USD' then 1 
       when currency = 'BHT' then 2
       when currency = 'JPY' then 3
       when currency = 'MYR' then 4
       else 5
    end

or a bit more compact but Oracle specific:

order by decode(currency, 'USD', 1, 'BHT', 2, 'JPY', 3, 'MYR', 4, 5)

The above solution using numbers to defined the sort order will not automatically sort currencies correctly that aren't mentioned in the case/decode expression.

To simply put USD at the front and don't care about the rest, the "generated" order criteria must be a character value as well. You can use the following in that case:

order by 
    case 
       when currency = 'USD' then '001' 
       else currency
    end

Which uses an "alphabetical" ordering. This works because characters are sorted after the number digits. (Using 'AAA' instead of '001' would work as well).

回答2:

To make sure Your sort is "flexible" and will work with all currencies do this:

SELECT <columns>
FROM <tableName>
ORDER BY DECODE(currencyColumn,'USD', 1, 2), currencyColumn

回答3:

A more detailed way of doing this, if you are interesting in sorting certain values to the beginning or end, but have those sorted in their group:

order by
  case when currency in ('USD', 'CAD') 
    then '000'||currency
  when currency in ('ZWD', 'HTG')
    then 'ZZZ'||currency
  else currency 
  end

This will put the USD and CAD at the top of the list (sorted), ZWD and HTG at the bottom, and the rest sorted between those.

回答4:

Maybe this will help you:

order by decode(currency, 'USD', 1, 2)

or using case

  order by 
      case 
        when currency = 'USD' then 1 
        else 2
      end

回答5:

One more variant with regexp like function FIELD() in MySQL:

select
meas_code,
to_number(regexp_replace(meas_code, replace('(meas1,meas2,meas3)', ',', '|'), instr(replace('(meas1,meas2,meas3)', ',', '|'), meas_code))) ordr
from (select cast(column_value as varchar2(10)) as meas_code from xmltable('''meas1'',''meas2'',''meas3'''))
order by 2

回答6:

You could do the following:

SELECT 
  * 
FROM
  yourtable
ORDER BY
  REPLACE(FIND_IN_SET(currency,'USD,BHT,JPY,MYR'),0,'Z')

回答7:

I needed to do the same, but with multiple columns, and found Grzegorz W's answer the best for this, with the following simple addition:

SELECT <columns>
FROM <tableName>
ORDER BY DECODE(currencyColumn,'USD', 1, 2), currencyColumn, anotherColumn;

来源：https://stackoverflow.com/questions/13339589/custom-order-in-oracle-sql

标签

sql

Oracle

sql-order-by