That’s the GroupBy operator. Are you using LINQ to Objects? Here’s an example: using System; using System.Collections.Generic; using System.Linq; public class Test { static void Main() { var users = new[] { new { User=”Bob”, Hobby=”Football” }, new { User=”Bob”, Hobby=”Golf” }, new { User=”Bob”, Hobby=”Tennis” }, new { User=”Sue”, Hobby=”Sleeping” }, new { User=”Sue”, … Read more
Can you not use a subselect with the order by clause in, and then group concat the values? Something like SELECT ID, GROUP_CONCAT(Val) FROM ( SELECT ID, Val FROM YourTable ORDER BY ID, Val ) GROUP BY ID;
Sure, see http://dev.mysql.com/doc/refman/…tions.html#function_group-concat: SELECT student_name, GROUP_CONCAT(DISTINCT test_score ORDER BY test_score DESC SEPARATOR ‘ ‘) FROM student GROUP BY student_name;
I believe that the answer you need is a user-defined aggregate, similar to this one: CREATE FUNCTION gc_init(dummy VARCHAR(255)) RETURNING LVARCHAR; RETURN ”; END FUNCTION; CREATE FUNCTION gc_iter(result LVARCHAR, value VARCHAR(255)) RETURNING LVARCHAR; IF result=”” THEN RETURN TRIM(value); ELSE RETURN result || ‘,’ || TRIM(value); END IF; END FUNCTION; CREATE FUNCTION gc_comb(partial1 LVARCHAR, partial2 LVARCHAR) … Read more
Consider using LISTAGG function in case you’re on 11g: select grp, listagg(name,’,’) within group( order by name ) from name_table group by grp sqlFiddle upd: In case you’re not, consider using analytics: select grp, ltrim(max(sys_connect_by_path (name, ‘,’ )), ‘,’) scbp from (select name, grp, row_number() over (partition by grp order by name) rn from tab … Read more
One somewhat hacky way to do it is to post-process the result of GROUP_CONCAT: substring_index(group_concat(s.title SEPARATOR ‘,’), ‘,’, 3) as skills Of course this assumes that your skill names don’t contain commas and that their amount is reasonably small. fiddle A feature request for GROUP_CONCAT to support an explicit LIMIT clause is unfortunately still not … Read more
SELECT a.nid, GROUP_CONCAT(b.name ORDER BY b.id) DepartmentName FROM Notes a INNER JOIN Positions b ON FIND_IN_SET(b.id, a.forDepts) > 0 GROUP BY a.nid SQLFiddle Demo
You can use ORDER BY inside the GROUP_CONCAT function in this way: SELECT li.client_id, group_concat(li.percentage ORDER BY li.views ASC) AS views, group_concat(li.percentage ORDER BY li.percentage ASC) FROM li GROUP BY client_id
Since 9.0 this is even easier: SELECT id, string_agg(some_column, ‘,’) FROM the_table GROUP BY id
GROUP_CONCAT has DISTINCT attribute: SELECT GROUP_CONCAT(DISTINCT categories ORDER BY categories ASC SEPARATOR ‘ ‘) FROM table