SQL行合并

mysql: groupconcat

mysql> SELECT student_name,

    ->     GROUP_CONCAT(test_score)

    ->     FROM student

    ->     GROUP BY student_name;

Or:

mysql> SELECT student_name,

    ->     GROUP_CONCAT(DISTINCT test_score

    ->               ORDER BY test_score DESC SEPARATOR ' ')

    ->     FROM student

    ->     GROUP BY student_name;


oracle: sys_connect_by_path()
如：select name, ltrim(sys_connect_by_path(email,','),',') email from(
select name,email,
row_number() over(partition by name order by email) rn,
count(*) over(partition by name) cnt
from student
) where level = cnt
start with rn = 1
connect by prior name = name and prior rn + 1 = rn