摘要： 大小写转换函数LOWER('SQL Course') = sql courseUPPER('SQL Course') = SQL COURSEINITCAP('SQL Course') = Sql CourseSELECT employee_id, last_name, department_idFROM employeesWHERE last_name = 'higgins';SELECT employee_id, last_name, department_idFROM employeesWHERE LOWER(last_na 阅读全文