MySQL IF Result Count 0 Return Message - mysql

Question

I need the following query to return a message, such as "No Result" if the Record Count = 0.
set #ID_CARTERA = 1;
select
LEFT(A.F_ANOTRIMESTRE, 4 ) Year,
RIGHT(A.F_ANOTRIMESTRE, 2 ) Quarter,
ROUND ( A.POR_RENTABILIDAD, 2 ) Quarterly_Yield
from dr_rent_carteras_trimestres A
where A.ID_CARTERA = #ID_CARTERA
And (LEFT(A.F_ANOTRIMESTRE, 4 ) = ( select MAX(left(F_ANOTRIMESTRE, 4 ) ) - 0
from dr_rent_carteras_trimestres
where ID_CARTERA = #ID_CARTERA )
and
RIGHT(A.F_ANOTRIMESTRE, 2 ) = 12)

Answer 1

you can trick the system like this:
generate a query to return COUNT(*). This will always return a row, even if there are zero rows to count
Left join your main query with the COUNT(*) query. Use Case statement to replace the results with "No Results".
So, the resulting query will look like (assumption - the main query returns zero or one record only - thus there is no ON clause in the LEFT JOIN!!!!):
set #ID_CARTERA = 1;
select
CASE cnt WHEN 0 THEN "No Results" ELSE Year END,
Quarter,
Quarterly_Yield
FROM
(select count(*) AS cnt
from dr_rent_carteras_trimestres A
where A.ID_CARTERA = #ID_CARTERA
And (LEFT(A.F_ANOTRIMESTRE, 4 ) = ( select MAX(left(F_ANOTRIMESTRE, 4 ) ) - 0
from dr_rent_carteras_trimestres
where ID_CARTERA = #ID_CARTERA )
and
RIGHT(A.F_ANOTRIMESTRE, 2 ) = 12) ) cnt_tbl
LEFT JOIN
( select
LEFT(A.F_ANOTRIMESTRE, 4 ) Year,
RIGHT(A.F_ANOTRIMESTRE, 2 ) Quarter,
ROUND ( A.POR_RENTABILIDAD, 2 ) Quarterly_Yield
from dr_rent_carteras_trimestres A
where A.ID_CARTERA = #ID_CARTERA
And (LEFT(A.F_ANOTRIMESTRE, 4 ) = ( select MAX(left(F_ANOTRIMESTRE, 4 ) ) - 0
from dr_rent_carteras_trimestres
where ID_CARTERA = #ID_CARTERA )
and
RIGHT(A.F_ANOTRIMESTRE, 2 ) = 12) ) main_tbl
The same thing can be accomplished with UNION. Ask in the comments if you wish me to show how