and 1=1 ${if(len(j_item) == 0 , "" , " and item_name_j in ('" + j_item + "') ")}
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参数这样设置,为空时不生效
参数为空查询全部即可
下拉框参数为空选择全部- FineReport帮助文档 - 全面的报表使用教程和学习资料 https://help.fanruan.com/finereport/doc-view-2394.html
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SELECT * FROM 订单 WHERE 1=1 ${if(len(area) == 0,"","and 货主地区 = '" + area + "'")}