sqlsum函数子件存在为null的结果直接返回null的sql语句

Question

sql查询数据求和，类似于订单一样的表，计算订单的价格求和，但是如果这个订单下面有一个价格为null或者是0那直接不进行计算返回0或者null

sql如下

        SELECT    pppd.ASSEMBLY_ITEM_CODE,
            pppd.DESCRIPTION AS DESCRIPTION,
            ppasg.CONTRACT_UNIT,
            pple.GROUP_SHORT_NAME,
            pas.ASSEMBLY_TYPE AS ASSEMBLY_TYPE,
            round( sum( pppd.COMPONENT_QUANTITY * ppl.UNIT_PRICE ), 7 ) AS price,
            round( sum( pppd.COMPONENT_QUANTITY * ppl.REAL_UNIT_PRICE ), 7 ) AS realPrice 
        FROM
            (
            SELECT
                a.* 
            FROM
                PPS_PARTS_PBOM_DETAILED a 
            WHERE
                (
                    SUBSTR( a.ASSEMBLY_ITEM_CODE, 0, 2 ) = 'FD' 
                    AND ( a.MFMRTG LIKE 'CG%' AND a.MFARTG LIKE 'ZZ%' ) 
                    OR SUBSTR( a.ASSEMBLY_ITEM_CODE, 0, 2 ) = 'DZ' 
                ) 
            ) pppd
            LEFT JOIN ( SELECT DISTINCT CONTRACT_UNIT, SUB_ASSEMBLY_NAME, AUDIT_STATUS FROM PPS_PARTS_ASSEMBLING ) ppasg ON pppd.DESCRIPTION = ppasg.SUB_ASSEMBLY_NAME 
            AND ppasg.AUDIT_STATUS = '0'
            LEFT JOIN PPS_PROD_LINE pple ON pple.PROD_LINE_GROUP_CODE = ppasg.CONTRACT_UNIT 
            AND pple.TYPE = '2'
            LEFT JOIN PPS_PARTS_LIBRARY ppl ON ppl.COMPONENT_ITEM_CODE = pppd.COMPONENT_ITEM_CODE 
            AND ppl.CONTRACT_UNIT = ppasg.CONTRACT_UNIT 
            AND ppl.AUDIT_STATUS = '0' 
            AND ppl.TYPE = '2'
            LEFT JOIN PPS_PARTS_ASSEMBLY_SPECIAL pas ON pas.ASSEMBLY_ITEM_CODE = pppd.ASSEMBLY_ITEM_CODE 
        GROUP BY
            pppd.ASSEMBLY_ITEM_CODE,
            pppd.DESCRIPTION,
            ppasg.CONTRACT_UNIT,
            pas.ASSEMBLY_TYPE,
            pple.GROUP_SHORT_NAME 

查看其中某个订单下面存在有价格为null的

想要的效果就是，如果订单下面有一个价格为null直接sum的结果也改为null

我想要达到的结果

Answer 1

不是道你用的什么sql，hive 的话，sum中含有null，那么结果必然为null。

 select sum(null+1)
             -> ;
 _col0
-------
 NULL
(1 row)

 select sum(null*3);
 _col0
-------
 NULL
(1 row)