CREATE TABLE Ref_Detention_Type (detention_type_description VARCHAR, detention_type_code VARCHAR)
CREATE TABLE Detention (detention_type_code VARCHAR)

What are the code and description of the least frequent detention type ?
SELECT T1.detention_type_code, T2.detention_type_description FROM Detention AS T1 JOIN Ref_Detention_Type AS T2 ON T1.detention_type_code = T2.detention_type_code GROUP BY T1.detention_type_code ORDER BY COUNT(*) LIMIT 1
SELECT "T1"."detention_type_code", "T2"."detention_type_description" FROM "Detention" AS "T1" JOIN "Ref_Detention_Type" AS "T2" ON "T1"."detention_type_code" = "T2"."detention_type_code" GROUP BY "T1"."detention_type_code" ORDER BY COUNT(*) NULLS FIRST LIMIT 1