我找不到比这更简单的方法：
SELECt majors.program_name, options.program_name, specs.program_name, subspecs.program_name, majors.preFROM @Programs majorsLEFT JOIN @Programs options ON majors.pre = options.pre AND options.program_level = 'Option'LEFT JOIN @Programs specs ON options.pre = specs.pre AND specs.program_level = 'Specialty'LEFT JOIN @Programs subspecs ON specs.pre = subspecs.pre AND subspecs.program_level = 'Subspecialty'WHERe majors.program_level = 'Major'
编辑：纠正错字“ Speciality”，它现在应该可以使用。
