SQL Return Null if One Column is Null (Opposite of COALESCE())

In advance, I would like to say thanks for the help. This is a great community and I've found many programming answers here.

I have a table with multiple columns, 5 of which contain dates or null.

I would like to write an sql query that essentially coalesces the 5 columns into 1 column, with the condition that if 1 of the five columns contains a "NULL" value, the returned value is null. Essentially the opposite of the coalesce condition of returning the first non-null, I want to return the first nul开发者_Go百科l. If none are null, returning the greatest of the 5 dates would be optimal, however I can settle with returning any one of the 5 dates.

    C1         C2          C3        C4        C5
    --         --          --        --        --
 1/1/1991   1/1/1991    1/1/1991  1/1/1991  2/2/1992
   NULL     1/1/1991    1/1/1991  1/1/1991  1/1/1991

Query Returns:

    C1
    --
 2/2/1992
   NULL

Thank you very much.

(Server is MSSQL2008)

select greatest(c1, c2, c3, c4, c5)
from table;

Life can be so easy :-)

(edit: works on Oracle)

Without overthinking it:

SELECT
  CASE WHEN c1 is null or c2 is null or c3 is null or c4 is null or c5 is null
       THEN null
       ELSE c1
  END
FROM mytable

My edit is as follows:

CASE 
 WHEN (c1 >= c2 AND c1 >= c3) THEN c1
 WHEN (c2 >= c1 AND c2 >= c3) THEN c2
 WHEN (c3 >= c1 AND c3 >= c2) THEN c3
END

Try this:

SELECT
    CASE WHEN t1.SomeDate IS NULL THEN NULL ELSE MAX(t1.SomeDate) END AS TheVal
FROM
(
SELECT C1 AS SomeDate FROM Table_1
UNION ALL
SELECT C2 AS SomeDate  FROM Table_1
UNION ALL
SELECT C3 AS SomeDate FROM Table_1
UNION ALL
SELECT C4 AS SomeDate FROM Table_1
UNION ALL
SELECT C5 AS SomeDate FROM Table_1
) t1
GROUP BY
t1.SomeDate

perhaps a variation on coalesce (replace -1 with an invalid value)?

SELECT CASE WHEN COALESCE(C1,C2,C3,C4,C5,-1) = -1 THEN NULL ELSE COALESCE(C1,C2,C3,C4,C5) END

Maybe with LEAST? I don't know how this works with NULL.

SELECT 
    CASE WHEN C1 IS NULL THEN C2 WHEN C1 IS NULL AND C2 IS NULL THEN C3 WHEN C1 IS NULL AND C2 IS NULL AND C3 IS NULL THEN C4 WHEN C1 IS NULL AND C2 IS NULL AND C3 IS NULL AND C4 IS NULL THEN C5 ELSE C1 END AS REQUIREDNOTNULLVALUE 
FROM 
TABLE1