此sql语句包括了两个聚合函数做除法求百分比，并保留两位小数，直接输出字符串形式的百分比。以及对case when在聚合函数的应用。
SELECT ss.SS_NAME,SS_ID,
COUNT(ea.EA_ID) AS EACounts,--回单交换单个数
COUNT(eb.EB_ID) AS EBCounts,--交换单个数
COUNT(ps.PS_ID) AS PSCounts,--签收单个数
COUNT(SW_ID) AS SWCounts,--运单数个数
COUNT(CASE WHEN PS_STATUS=1 THEN 'PS_ID' END) AS PSSCounts,--签收成功单个数
CAST(CONVERT( DECIMAL(18,2),COUNT(ea.EA_ID)/CAST(ISNULL(NULLIF(COUNT(EB_ID),0),1) AS FLOAT)*100)AS VARCHAR(10))+'%' AS ReturnPer,--回单率
CAST(CONVERT(DECIMAL(18,2),COUNT(ps.PS_ID)/CAST(ISNULL(NULLIF(COUNT(SW_ID),0),1) AS FLOAT)*100)AS VARCHAR(10))+'%' AS SignPer ,--签收率
CAST(CONVERT(DECIMAL(18,2),COUNT(CASE WHEN PS_STATUS=1 THEN 'PS_ID' END)/CAST(ISNULL(NULLIF(COUNT(PS_ID),0),1) AS FLOAT)*100 ) AS VARCHAR(10))+'%' AS SignSucPer --签收成功率
FROM dbo.SBD_WAYBILL sw
LEFT JOIN dbo.PDA_SININFO ps ON sw.SW_ID=ps.PS_SW_ID
LEFT JOIN dbo.SBD_EXCHANGE_RETURN_BILL ea ON ea.EA_SW_ID=sw.SW_ID
LEFT JOIN dbo.SBD_EXCHANGE_BILL eb ON eb.EB_SW_ID=sw.SW_ID
LEFT JOIN dbo.SBD_STATION ss ON ss.SS_ID=sw.SW_DESTINATION
WHERE 1=1 GROUP BY SS_ID,SS_NAME
ORDER BY SS_NAME
