Câu truy vấn tổng hợp số lượng chứng từ được tạo theo từng người dùng

Sử dụng câu truy vấn sau để tổng hợp số lượng từng chứng từ được tạo (Sales Document) theo từng người dùng

select "U_NAME" "User Name",
 sum(case when "DocType" = 'SQ' then "Count" else 0 end) as "SQ",
 sum(case when "DocType" = 'SO' then "Count" else 0 end) as "SO",
 sum(case when "DocType" = 'PL' then "Count" else 0 end) as "PL",
 sum(case when "DocType" = 'DN' then "Count" else 0 end) as "DN",
 sum(case when "DocType" = 'AR' then "Count" else 0 end) as "AR",
 sum(case when "DocType" = 'CM' then "Count" else 0 end) as "CM"
from
(
SELECT T1."U_NAME", 'SQ' "DocType", COUNT(T2."DocNum") AS "Count" FROM OUSR T1 LEFT JOIN OQUT T2 ON T1."USERID" = T2."UserSign" GROUP BY T1."U_NAME"
Union
SELECT T1."U_NAME", 'SO' "DocType", COUNT(T2."DocNum") AS "Count" FROM OUSR T1 LEFT JOIN ORDR T2 ON T1."USERID" = T2."UserSign" GROUP BY T1."U_NAME"
Union
SELECT T1."U_NAME", 'PL' "DocType", COUNT(T2."AbsEntry") AS "Count" FROM OUSR T1 LEFT JOIN OPKL T2 ON T1."USERID" = T2."OwnerCode" GROUP BY T1."U_NAME"
Union
SELECT T1."U_NAME", 'DN' "DocType", COUNT(T2."DocNum") AS "Count" FROM OUSR T1 LEFT JOIN ODLN T2 ON T1."USERID" = T2."UserSign" GROUP BY T1."U_NAME"
Union
SELECT T1."U_NAME", 'AR' "DocType", COUNT(T2."DocNum") AS "Count" FROM OUSR T1 LEFT JOIN OINV T2 ON T1."USERID" = T2."UserSign" GROUP BY T1."U_NAME"
Union
SELECT T1."U_NAME", 'CM' "DocType", COUNT(T2."DocNum") AS "Count" FROM OUSR T1 LEFT JOIN ORIN T2 ON T1."USERID" = T2."UserSign" GROUP BY T1."U_NAME"
) 
group by "U_NAME"
having 
sum(case when "DocType" = 'SQ' then "Count" else 0 end)>0 or 
sum(case when "DocType" = 'SO' then "Count" else 0 end)>0 or
sum(case when "DocType" = 'PL' then "Count" else 0 end)>0 or
sum(case when "DocType" = 'DN' then "Count" else 0 end)>0 or
sum(case when "DocType" = 'AR' then "Count" else 0 end)>0 or
sum(case when "DocType" = 'CM' then "Count" else 0 end)>0