money为double(8,2) double ----->char char(cast(money as decimal(8,2)))
char ------->double cast(cast(char(cast(a.money as decimal(8,2))) as decimal(8,2)) as double)
money为decimal(8,2) decimal ------->char Digits(money)
char ------->decimal cast(Digits(money) as decimal(8,2))
money为date date ------>char char(money)
char ------>date date(trim(char(money)))
money为bigint bigint ---->char char(money)
char ----->bigint cast(char(money) as bigint)