Sql 列中的数据而不是行中的数据

我想在一个程序中显示模块，与程序一起显示为一行，而不是为每个程序显示多行模块

    SELECT program.program_title as program, course_module.title as unit
    FROM program_module
    INNER JOIN program
        ON program_module.program_id = program.id
    INNER JOIN course_module 
        ON program_module.course_module_id = course_module.id

生成：

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如何使其显示为这样：

您可以这样做：

SELECT program.program_title as program, LISTAGG(course_module.title, ',') WITHIN GROUP (ORDER BY course_module.title) as unit
FROM program_module
INNER JOIN program
    ON program_module.program_id = program.id
INNER JOIN course_module 
    ON program_module.course_module_id = course_module.id
GROUP BY program.program_title

---

您可以这样做：

SELECT program.program_title as program, LISTAGG(course_module.title, ',') WITHIN GROUP (ORDER BY course_module.title) as unit
FROM program_module
INNER JOIN program
    ON program_module.program_id = program.id
INNER JOIN course_module 
    ON program_module.course_module_id = course_module.id
GROUP BY program.program_title

我在这儿拉小提琴

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sqlfiddle here

如果需要单独的列，而不是单个逗号分隔的列，可以使用pivot。11g中有一个内置的pivot命令；或者你也可以用老式的方式：

SELECT program,
    MAX(CASE WHEN pos = 1 THEN unit END) AS unit1,
    MAX(CASE WHEN pos = 2 THEN unit END) AS unit2,
    MAX(CASE WHEN pos = 3 THEN unit END) AS unit3,
    MAX(CASE WHEN pos = 4 THEN unit END) AS unit4
FROM (
  SELECT program.id as program_id,
      program.program_title as program,
      course_module.title as unit,
      row_number() over (partition by program.id
          order by course_module.title) as pos
    FROM program_module
    INNER JOIN program
        ON program_module.program_id = program.id
    INNER JOIN course_module 
        ON program_module.course_module_id = course_module.id
)
group by program_id, program
order by program;

无论哪种方式，您都需要知道可能有多少个模块，并对它们进行处理（在此版本中添加更多case语句）

---

.

如果需要单独的列，而不是单个逗号分隔的列，可以使用透视。11g中有一个内置的pivot命令；或者你也可以用老式的方式：

SELECT program,
    MAX(CASE WHEN pos = 1 THEN unit END) AS unit1,
    MAX(CASE WHEN pos = 2 THEN unit END) AS unit2,
    MAX(CASE WHEN pos = 3 THEN unit END) AS unit3,
    MAX(CASE WHEN pos = 4 THEN unit END) AS unit4
FROM (
  SELECT program.id as program_id,
      program.program_title as program,
      course_module.title as unit,
      row_number() over (partition by program.id
          order by course_module.title) as pos
    FROM program_module
    INNER JOIN program
        ON program_module.program_id = program.id
    INNER JOIN course_module 
        ON program_module.course_module_id = course_module.id
)
group by program_id, program
order by program;

无论哪种方式，您都需要知道可能有多少个模块，并对它们进行处理（在此版本中添加更多case语句）

---

.

您使用的是什么数据库？您希望数据以单独的列显示，还是以逗号分隔的字符串（如编程、网络等）显示在一列中？Oracle编辑：对不起，我准备好了日期、单独的列。您使用的是什么数据库？您希望数据在单独的列中还是在一列中使用逗号分隔的字符串（如编程、网络等）？Oracle编辑：抱歉，我准备好将其作为日期、单独的列。