MSYQL数据操作语言（DML)

　　一、select语法　　SELECT　　[ALL | DISTINCT | DISTINCTROW ]　　[HIGH_PRIORITY]　　[STRAIGHT_JOIN]　　[SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]　　[SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]　　select_expr [, select_expr ..