错误代码： 1248 Every derived table must have its own alias

1、错误描述

1 queries executed, 0 success, 1 errors, 0 warnings

查询：SELECT stu_id, (SELECT stu_name FROM t_student_info t WHERE t.stu_id = t.stu_id) stu_name FROM (SELECT SUM( CASE course WHEN '敮..

错误代码： 1248
Every derived table must have its own alias

执行耗时   : 0 sec
传送时间   : 0 sec
总耗时      : 0 sec

2、错误原因

SELECT
  stu_id,
  (SELECT
    stu_name
  FROM
    t_student_info t
  WHERE t.stu_id = t.stu_id) stu_name
FROM
  (SELECT
    SUM(
      CASE
        course
        WHEN '数学'
        THEN Score
        ELSE 0
      END
    ) 数学,
    SUM(
      CASE
        course
        WHEN '语文'
        THEN score
        ELSE 0
      END
    ) 语文,
    SUM(
      CASE
        course
        WHEN '英语'
        THEN score
        ELSE 0
      END
    ) 英语,
    stu_id
  FROM
    t_score_info
  GROUP BY stu_id)

3、解决办法

SELECT
	*
FROM
	(
		SELECT
			stu_no
		FROM
			t_student_info
		UNION
			SELECT
				stu_no
			FROM
				t_student_info
	) student;

在后面给联合查询取个别名student