variables in SQL for monetdb

Question

I am confused whether at-sign variables could ever work in MonetDB. Is it standard SQL or only mySQL? (See eg this answer here on SO.) MonetDB claims to support SQL:2003 (full feature list here , hard for me to parse), but this is what they say on variables.

The following line fails in MonetDB complaining about the unexpected symbol : . But is there a way to get this work? I see no way to combine a SET (after DECLARE ) with SELECT .

SELECT @firstq := QUANTILE(share26_2007,0.25) FROM sys.share26_2007;

(Afterwards, the following is the intended use case:)

SELECT peorglopnr, CASE WHEN share26_2007 < @firstq THEN 1

Answer 1

As already pointed out in the comments, @ variables are not standard SQL.

Using DECLARE and SET would work::

DECLARE firstq double;
SET firstq = ( SELECT quantile(share26_2007, 0.25) FROM share26_2007 );

SELECT peorglopnr, CASE WHEN share26_2007 < firstq THEN 1 .....

Notes:

• What I understand from your example is that you have a table share26_2007 which has a column share26_2007 . I followed this assumption.
• I declared the variable firstq as double . Your example does not specify the type of column share26_2007 . Change the variable type accordingly.
• When setting the value of a variable to the result of a SELECT that returns an atomic value, you do need parentheses around the SELECT.
• At this moment quantile seems not to work correctly in MonetDB (see https://www.monetdb.org/bugzilla/show_bug.cgi?id=4076 ), but this is unrelated to your question. The syntax above works (you may want to verify that by replacing quantile with sys.quantile )