COUNT个同一列的多种类型

Question

在我当前的查询中：

SELECT COUNT(WC.ID) AS "Regions" 
FROM WHOLE_FEATURES_PDB_CHAINS AS WC 
;

我将COUNT(WC.ID) AS "Regions" 。 但是，我们有多个具有WC.Type的区域，可以是1,2,3,4 。 我需要将每种类型出现的次数都计入COUNT(WC.ID) AS "Region_1" ， COUNT(WC.ID) AS "Region_2" ...，具体取决于WC.Type 。 有什么办法可以在一个查询中解决这个问题？ 我正在查看MySQL IF ，但不知道如何将其集成到count函数中。

我需要将其放在一行中（此处显示的查询已减少，这是一个较大的查询）

SELECT COUNT(WC.ID) AS "Region_1" , COUNT(WC.ID) AS "Region_2" ...

如果有人感兴趣，这是完整的查询：

SELECT PCS.PDB_id, PCS.Chain, PPA.ENSEMBL_start, PPA.ENSEMBL_end, PPA.eValue, PIN.TITLE AS "pdbTitle", COUNT(WC.ID) AS "Regions" 
FROM PDB_Chains AS PCS 
LEFT JOIN WHOLE_FEATURES_PDB_CHAINS AS WC ON WC.PDB_CHAIN_ID = PCS.idPDB_chains, PDB_protein_alignment PPA, PDB_INFOS PIN 
WHERE PCS.idPDB_chains = PPA.idPDB_Chains 
AND PCS.PDB_id = PIN.PDB_ID 
AND PPA.idProteins = (SELECT idProteins from Proteins WHERE ENSEMBL_protein_id = "'+submittedID+'") 
GROUP BY PCS.PDB_id, PCS.Chain ORDER BY PCS.PDB_id;

---

这是根据您的喜好而定的解决方案

SELECT PIN.TITLE AS "pdbTitle", COUNT(CASE WHEN WC.STRUCTURAL_FEATURES_ID = 1 then 1 end) AS "PPInterface" , COUNT(CASE WHEN WC.STRUCTURAL_FEATURES_ID = 4 then 1 end) AS "flexibleRegions" 
FROM PDB_Chains AS PCS LEFT JOIN WHOLE_FEATURES_PDB_CHAINS AS WC ON WC.PDB_CHAIN_ID = PCS.idPDB_chains, PDB_protein_alignment PPA, PDB_INFOS PIN 
WHERE PCS.idPDB_chains = PPA.idPDB_Chains 
AND PCS.PDB_id = PIN.PDB_ID 
AND PPA.idProteins = (SELECT idProteins from Proteins WHERE ENSEMBL_protein_id = "ENSP00000256078.4") 
GROUP BY PCS.PDB_id, PCS.Chain ORDER BY PCS.PDB_id;

Answer 1

Select
...
...
sum(if WC.ID = 1 then 1 else 0) as Region1,
sum(if WC.ID = 2 then 1 else 0) as Region2,
sum(if WC.ID = 3 then 1 else 0) as Region3,
sum(if WC.ID = 4 then 1 else 0) as Region4

可能会做您想要的。

Answer 2

您可以在聚合函数中使用case when语句。

尝试这个 。

count（WC.type = 1然后1结束的情况）作为region_1，类似地对另一列重复。

Answer 3

您可以将GROUP BY与COUNT以获取所需的结果，例如：

SELECT WC.Type, COUNT(WC.ID) AS "Regions" 
FROM WHOLE_FEATURES_PDB_CHAINS AS WC 
GROUP BY WC.Type;

更新资料

如果要将计数作为每个区域的枢轴列，则可以编写内部SELECT查询，例如：

SELECT
 (SELECT COUNT(ID) FROM WHOLE_FEATURES_PDB_CHAINS WHERE type = 1) AS "Region_1",
 (SELECT COUNT(ID) FROM WHOLE_FEATURES_PDB_CHAINS WHERE type = 2) AS "Region_2",
other_column
FROM WHOLE_FEATURES_PDB_CHAINS AS WC
WHERE <some condition>;