Question

如果我的答案在其他地方发布，我道歉，但我已经搜索过，但无法找到它。我试图在SQL中完成以下（使用H2）：这是一个有效的查询：

SELECT
  t38.patient_id,
  t38.id AS t38id,
  t38.effective_time_start AS t38ets,
  t38.effective_time_end AS t38ete,
  t36.id AS t36id,
  t36.effective_time_start AS t36ets,
  t36.effective_time_end AS t36ete
FROM View1 AS t38
INNER JOIN View2 AS t36
  ON t38.patient_id = t36.patient_id
  AND t36.effective_time_start < t38.effective_time_start

我需要做的是在max上设置t36.effective_time_start，在t38.id设置一个组，如下所示：

SELECT
  t38.patient_id,
  t38.id AS t38id,
  t38.effective_time_start AS t38ets,
  t38.effective_time_end AS t38ete,
  t36.id AS t36id,
  MAX(t36.effective_time_start) AS t36ets,
  t36.effective_time_end AS t36ete
FROM View1 AS t38
INNER JOIN View2 AS t36
  ON t38.patient_id = t36.patient_id
  AND t36.effective_time_start < t38.effective_time_start
GROUP BY t38.id

这不起作用。

这是我想要完成的事情：对于每个患者ID，我有一组t38s和t36s。我想要关于它们的所有数据，加在一起，但我只想要在t38之前t36开始的行。我也只想要每个t38id一行，并且该行需要是最近的（最大开始时间）t36，但它不能只是最大值，它必须仍然在t38开始时间之前。

DISTINCT ON和RANK ON PARTITION都是我无法尝试的方法，因为它们在H2中不受支持。想法？

Answer 1

我对您的数据不太熟悉，但是会有以下工作吗？（可能需要一些调整才能达到预期效果）

SELECT t38.patient_id,
t38.id AS t38id,
t38.effective_time_start AS t38ets,
t38.effective_time_end AS t38ete,
t36.id AS t36id,
t36.effective_time_start AS t36ets,
t36.effective_time_end AS t36ete

FROM View1 AS t38
INNER JOIN View2 AS t36
ON t38.patient_id = t36.patient_id
AND t36.effective_time_start < t38.effective_time_start
JOIN (SELECT MAX(View1.effective_time_start) MaxDate,
         view1.paitent_id
  FROM View1
  INNER JOIN View2 
  ON View1.patient_id = View2.patient_id
  WHERE View2.effective_time_start < View1.effective_time_start
  GROUP BY View1.paitent_id) MaxDateCalc
ON MaxDateCalc.paitent_id = t38.paitent_id
and MaxDateCalc.MaxDate = t38.effective_time_start

Answer 2

我不确定这是否有帮助，但在我的测试中，您的第二个查询似乎唯一的错误就是分组依据。在一些基本的临时表中，我得到了每个正确的1行，它是最大值。

SELECT
  t38.patient_id,
  t38.id AS t38id,
  t38.effective_time_start AS t38ets,
  t38.effective_time_end AS t38ete,
  t36.id AS t36id,
  MAX(t36.effective_time_start) AS t36ets,
  t36.effective_time_end AS t36ete
FROM View1 AS t38
INNER JOIN View2 AS t36
  ON t38.patient_id = t36.patient_id
  AND t36.effective_time_start < t38.effective_time_start
GROUP BY t38.patient_id,
  t38.id AS t38id,
  t38.effective_time_start AS t38ets,
  t38.effective_time_end AS t38ete,
  t36.id AS t36id,
  t36.effective_time_end AS t36ete

SQL认为，比“由前n组成”更复杂

2 个答案: