SQL - 多列成行答案

【问题标题】：SQL - multiple columns into rowsSQL - 多列成行
【发布时间】：2014-01-31 00:25:14
【问题描述】：

我正在使用 Oracle，我想将一个查询转换为多行。

这是我的查询：

SELECT I.cd_curso, 
       I.cd_discip, 
       ND.ds_discip, 
       I.cd_turma_t, 
       I.cd_turma_p, 
       I.cd_turma_l, 
       I.cd_turma_tp, 
       I.cd_turma_e, 
       I.cd_turma_o, 
       I.cd_turma_c, 
       I.cd_turma_s, 
       Count(*) AS alunos 
FROM   cse.v_vwinscri I, 
       cse.t_tbdiscip ND 
WHERE  I.cd_lectivo = 201314 
       AND I.cd_discip = 911901 
       AND I.cd_discip = ND.cd_discip 
       AND I.cd_curso = 9885 
       AND ( I.cd_turma_t IS NOT NULL 
              OR I.cd_turma_p IS NOT NULL 
              OR I.cd_turma_l IS NOT NULL 
              OR I.cd_turma_tp IS NOT NULL 
              OR I.cd_turma_e IS NOT NULL 
              OR I.cd_turma_o IS NOT NULL 
              OR I.cd_turma_c IS NOT NULL 
              OR I.cd_turma_s IS NOT NULL ) 
GROUP  BY I.cd_curso, 
          I.cd_discip, 
          ND.ds_discip, 
          I.cd_turma_t, 
          I.cd_turma_p, 
          I.cd_turma_l, 
          I.cd_turma_tp, 
          I.cd_turma_e, 
          I.cd_turma_o, 
          I.cd_turma_c, 
          I.cd_turma_s 
ORDER  BY I.cd_curso, 
          I.cd_turma_t, 
          I.cd_turma_p, 
          I.cd_turma_l, 
          I.cd_turma_tp, 
          I.cd_turma_e, 
          I.cd_turma_o, 
          I.cd_turma_c, 
          I.cd_turma_s

我希望将结果 CD_TURMA_T、CD_TURMA_P 等转换为不同的行，如 CD_TURMA。好吧，基本上使用第一个字段作为键，其他字段作为值，将它们从列更改为行...

有可能吗？

【问题讨论】：

是的，这是可能的。只需查找有关 Oracle Pivot 的教程或stackoverflow.com/questions/17060044/…
写COALESCE(I.cd_turma_t, I.cd_turma_p, I.cd_turma_l, I.cd_turma_tp, ...) IS NOT NULL比较短

标签： sql oracle unpivot

【解决方案1】：

您可以像这样简单地使用UNION ALL：

WITH cte AS (
    SELECT I.cd_curso, 
           I.cd_discip, 
           ND.ds_discip, 
           I.cd_turma_t, 
           I.cd_turma_p, 
           I.cd_turma_l, 
           I.cd_turma_tp, 
           I.cd_turma_e, 
           I.cd_turma_o, 
           I.cd_turma_c, 
           I.cd_turma_s, 
           Count(*) AS alunos 
    FROM   cse.v_vwinscri I, 
           cse.t_tbdiscip ND 
    WHERE  I.cd_lectivo = 201314 
           AND I.cd_discip = 911901 
           AND I.cd_discip = ND.cd_discip 
           AND I.cd_curso = 9885 
           AND ( I.cd_turma_t IS NOT NULL 
                  OR I.cd_turma_p IS NOT NULL 
                  OR I.cd_turma_l IS NOT NULL 
                  OR I.cd_turma_tp IS NOT NULL 
                  OR I.cd_turma_e IS NOT NULL 
                  OR I.cd_turma_o IS NOT NULL 
                  OR I.cd_turma_c IS NOT NULL 
                  OR I.cd_turma_s IS NOT NULL ) 
    GROUP  BY I.cd_curso, 
              I.cd_discip, 
              ND.ds_discip, 
              I.cd_turma_t, 
              I.cd_turma_p, 
              I.cd_turma_l, 
              I.cd_turma_tp, 
              I.cd_turma_e, 
              I.cd_turma_o, 
              I.cd_turma_c, 
              I.cd_turma_s)
SELECT cd_curso, 
       cd_discip, 
       ds_discip, 
       cd_turma_t AS cd_trauma,
       alunos
FROM   cte
UNION ALL 
SELECT cd_curso, 
       cd_discip, 
       ds_discip, 
       cd_turma_p,
       alunos
FROM   cte
UNION ALL
SELECT cd_curso, 
       cd_discip, 
       ds_discip, 
       cd_turma_l,
       alunos 
FROM   cte
UNION ALL
SELECT cd_curso, 
       cd_discip, 
       ND.ds_discip, 
       cd_turma_tp,
       alunos 
FROM   cte
UNION ALL
SELECT cd_curso, 
       cd_discip, 
       ds_discip, 
       cd_turma_e, 
       alunos 
FROM   cte
UNION ALL
SELECT cd_curso, 
       cd_discip, 
       ds_discip, 
       cd_turma_o, 
       alunos 
FROM   cte
UNION ALL
SELECT cd_curso, 
       cd_discip, 
       ds_discip, 
       cd_turma_c, 
       alunos 
FROM   cte
UNION ALL
SELECT cd_curso, 
       cd_discip, 
       ds_discip, 
       cd_turma_s,
       alunos 
FROM   cte;

【讨论】：