Sql 当select不返回任何行时，是否有办法使用占位符？

我有一个表，

report\u total

，其中包含一些

total\u类型\u cd

（代码）的计算值，但不一定包含所有类型

如果没有相应的行，我希望在select中有一个占位符，以便

重命名的总金额
（
unitem\u cntrib
/
total\u contrib
..）的值为
0
，并且即使找不到值，我始终会得到8个项目的返回。我想，
COALESCE
函数可能会起作用，但我无法编写一个可以接受的查询

这些查询结果将进入pdf报告，因此我需要一些东西，即使它是0。现在，不会生成任何报告，因为如果all值不存在，则select不会返回任何行。下面是我的select语句，
$P{ReportID}
被输入到报告生成器中

SELECT  unitem_cntrib, total_cntrib, unitem_expnd, total_expnd,
        unitem_pldg, on_hand, tot_loan, unitem_loan
FROM
(select total_amt  from report_total where calculation_type_cd ='UNITEMIZED_PLUS_LUMPSUM' 
and total_type_cd = 'TOT_CNTRB' and report_info_id=$P{ReportID} ) AS  unitem_cntrib,
(select total_amt from report_total where calculation_type_cd ='GRANDTOTAL' 
and total_type_cd = 'TOT_CNTRB' and report_info_id=$P{ReportID} ) AS  total_cntrib,
(select total_amt from report_total where calculation_type_cd ='UNITEMIZED_PLUS_LUMPSUM' 
and total_type_cd = 'TOT_EXPND' and report_info_id=$P{ReportID} ) AS  unitem_expnd,
(select total_amt from report_total where calculation_type_cd ='GRANDTOTAL' 
and total_type_cd = 'TOT_EXPND' and report_info_id=$P{ReportID} ) AS  total_expnd,
(select total_amt from report_total where calculation_type_cd ='UNITEMIZED_PLUS_LUMPSUM' 
and total_type_cd = 'TOT_PLEDGE' and report_info_id=$P{ReportID} ) AS  unitem_pldg,
(select total_amt from report_total where calculation_type_cd ='LUMPSUM' 
and total_type_cd = 'TOT_CNTRB_BALANCE' and report_info_id=$P{ReportID} ) AS  on_hand,
(select total_amt  from report_total where calculation_type_cd ='LUMPSUM' 
and total_type_cd = 'TOT_LOAN_PRINCIPAL' and report_info_id=$P{ReportID} ) AS  tot_loan,
(select total_amt  from report_total where calculation_type_cd ='UNITEMIZED_PLUS_LUMPSUM' 
and total_type_cd = 'TOT_LOAN' and report_info_id=$P{ReportID} ) AS  unitem_loan

我认为您需要条件聚合：

select max(case when calculation_type_cd = 'UNITEMIZED_PLUS_LUMPSUM' 
                 and total_type_cd = 'TOT_CNTRB' 
                then total_amt end) as unitem_cntrib,
       max(case when calculation_type_cd = 'GRANDTOTAL'
                 and total_type_cd = 'TOT_CNTRB' 
                then total_amt end) as total_cntrib,
       . . . 
 from report_total rt
where rt.report_info_id = $P{ReportID};