Обсуждение: Count Columns

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Count Columns

От
"Ray Madigan"
Дата:
I haven't done very many complex queries in sql, and maybe Im thinking about
my problem wrong but:

Is there a way to count the number of null or not null columns in a row and
have an output column that has that count as the value?
I want to create a ranking of the row based upon the number of not null
columns are in the row.  I want to have to use as few seperate queries as
possible.

The table that i want to do the query on is either a view or a temporary
table, I guess depending on if I can do this easily or if brut force is
required, Or if I have to think of a new way to solve my problem.

The table is like

CREATE TABLE myTbl ( name varchar(5) primary key, a varchar(5), b
varchar(5), c varchar(5) );

ending table looks like

name |  a  |  b  |  c  |
foo  |  A  |     |  C  |
bar  |  A  |  B  |     |
baz  |  A  |  B  |  C  |

and I want the result to look like

foo 2
bar 2
baz 3

Thanks in Advance



Re: Count Columns

От
Bruno Wolff III
Дата:
On Wed, Feb 16, 2005 at 10:09:05 -0800, Ray Madigan <ray@madigans.org> wrote:
> 
> Is there a way to count the number of null or not null columns in a row and
> have an output column that has that count as the value?

One way to do this would be to create a CASE clause for each column that
returns 1 or 0 depending on whether the column is null or not and add
these expressions up.