case：

SELECT stdname,

max( CASE WHEN stdsubject = '语文' THEN  result ELSE 0 END) "语文",

max( CASE WHEN stdsubject = '数学' THEN  result ELSE 0 END) "数学",

max( CASE WHEN stdsubject = '物理' THEN  result ELSE 0 END) "物理" ,

max( CASE WHEN stdsubject = '化学' THEN result ELSE 0 END)  "化学"

FROM  std

GROUP BY stdname;