Concatenate column names in sql select statement if certain condition is met

Question

I have a SQL SELECT statement pulling 4 columns:

SELECT cmm_residence, cmm_packing, cmm_furniture, cmm_overage

These columns are simple no/yes values (0,1). I need an additional column Description to concatenate any 'Yes' values for that row.

For example: if the query returned 'Yes' for cmm_residence and cmm_furniture , the Description column should be cmm_residence,cmm_furniture .

Answer 1

Schema and insert statements:

 create table  mytable (cmm_residence varchar(5), cmm_packing varchar(5), cmm_furniture varchar(5), cmm_overage varchar(5));
 insert into mytable values('yes','no','no','yes');
 insert into mytable values('no','no','no','yes');
 insert into mytable values('yes','yes','no','yes');

Query:

 select cmm_residence, cmm_packing, cmm_furniture, cmm_overage,
 concat(case when cmm_residence='yes' then ' cmm_residence ,'end,
 case when cmm_packing='yes' then ' cmm_packing ,'end,
 case when cmm_furniture='yes' then ' cmm_furniture ,'end,
 case when cmm_overage='yes' then ' cmm_overage 'end)Description
 from mytable

Output:

cmm_residence	cmm_packing	cmm_furniture	cmm_overage	Description
yes	no	no	yes	cmm_residence, cmm_overage
no	no	no	yes	cmm_overage
yes	yes	no	yes	cmm_residence, cmm_packing, cmm_overage

db<fiddle here

Answer 2

You can use a CASE into your SELECT statement adding whatever logic you need like this:

SELECT cmm_residence, cmm_packing, cmm_furniture, cmm_overage, 
CASE
    WHEN cmm_residence = 1 THEN 'cmm_residence'
    WHEN  cmm_packing = 1  THEN 'cmm_packing'
    ELSE ''
END As 'Description' 
FROM Table

Just add as much cases with logic as you want, take into account this isn't quite performant query.