Source = Excel.CurrentWorkbook(){[Name="TbB"]}[Content],
#"TbC" = Table.TransformColumnTypes(Source,{{"NoDossier", Int64.Type}, {"Date", type datetime}, {"Espece", type text}, {"Race_Type", type text}, {"Nom", type text}, {"Date_Naiss", type datetime}, {"Sexe", type text}, {"Couleurs", type text}, {"IdAnimal", Int64.Type}, {"Observation", type text}, {"Caractère", type text}, {"DateDC", type datetime}}),
#"Requêtes fusionnées" = Table.NestedJoin(TbC, {"NoDossier"}, GrouperCat, {"NoDossier"}, "TbA_req", JoinKind.LeftOuter),
#"TbA_req développé" = Table.ExpandTableColumn(#"Requêtes fusionnées", "TbA_req", {"Cat."}, {"Cat."})
in
#"TbA_req développé"