COUNT个同一列的多种类型

Question

In my current query:

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

I COUNT(WC.ID) AS "Regions" . However, we have multiple regions with WC.Type can be 1,2,3,4 . I need to count each type occurrence into COUNT(WC.ID) AS "Region_1" , COUNT(WC.ID) AS "Region_2" ... depending on WC.Type . Is there any way to solve this in one query? I am looking at MySQL IF , yet do not know how to integrate it into the count function.

I need it to be in one row (the shown query here is reduced, it's a larger query)

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

Here is the complete query if anyone is interested:

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;

---

Here's the working solutin based on your kind answers

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

Might do what you want.

Answer 2

You can use case when statement inside your aggregate function.

Try this .

count(case when WC.type = 1 then 1 end) as region_1, similarly repeat for another column.

Answer 3

You can use GROUP BY with COUNT to get the required result, eg:

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

Update

If you want the counts as pivoted column for each region then you can write inner SELECT queries, eg:

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>;