MS Sql: Conditional ORDER BY ASC/DESC Question

问题

I want to to make to make the ordering in my query conditional so if it satisfiess the condition it should be ordered by descending

For instance:

SELECT * FROM Data ORDER BY SortOrder CASE WHEN @Direction = 1 THEN DESC END

回答1:

Don't change the ASC or DESC, change the sign of the thing being sorted-by:

SELECT * FROM table 
ORDER BY 
CASE WHEN @Direction = 1 THEN -id else id END asc;

The OP asks:

Guys, I am not the SQL Expert, please explain me what means the id and -id, does it controls the ordering direction?

id is just whatever column you're sorting by; -id is just the negation of that, id * -1. If you're sorting by more than one column, you'll need to negate each column:

SELECT * FROM table 
ORDER BY 
CASE WHEN @Direction = 1 THEN -id else id END 
CASE WHEN @Direction = 1 THEN -othercolumn else othercolumn END ;

If you're ordering by a non numeric column, you'll need to find an expression that makes that column "negative"; writing a function to do that may help.

回答2:

SELECT * 
FROM Data 
ORDER BY 
Case WHEN @Direction = 1 THEN SortOrder END DESC, 
Case WHEN 1=1 THEN SortOrder END

回答3:

You can also use a scheme which supports all column types:

SELECT <column_list> FROM <table> ORDER BY CASE WHEN @sort_order = 'ASC' AND @sort_column = '<column>' THEN <column> END ASC, CASE WHEN @sort_order = 'DESC' AND @sort_column = '<column>' THEN <column> END DESC

回答4:

I have done something like this

select productId, InventoryCount, 
    case 
    when @Direction = 1 then InventoryCount 
    else -InventoryCount 
    end as "SortOrder"
order by 3

来源：https://stackoverflow.com/questions/758655/ms-sql-conditional-order-by-asc-desc-question

标签

sql

sql-server

sql-order-by