以下是查询语句SELECT businessinformation.CTname,posrunningtab.CTnumber,posrunningtab.ClearingDate,posrunningtab.TradingHour,posrunningtab.TradeType,posrunningtab.term,posrunningtab.Ssn_Report,posrunningtab.ref_no,posrunningtab.authcode,posrunningtab.card_attr,posrunningtab.account,posrunningtab.amount,posrunningtab.poscomm,posrunningtab.acceptsi,posrunningtab.Tctnumber,posrunningtab.Tterm,posrunningtab.attr2,posrunningtab.cbbankfrom posrunningtableft join businessinformation on posrunningtab.CTnumber=businessinformation.CTnumberwhere posrunningtab.CTnumber='${ctnumber}'为什么where里面的ctnumber参数查询后返回的值会是空值。我的想法是,以ctnumber参数的值查询businessinformation表和posrunningtab表,在businessinformation表中根据ctnumber返回商户的名称,在下列报表中返回相应的商户名称的值,在posrunningtab表中根据ctnumber参数的值返回相应的所有交易记录至下列报表中。为什么在报表页面输入ctnumber要查询的数据,点击查询后没有返回相应的查询结果,是where语句的问题吗?businessinformation表 字段posrunningtab表字段