java代码：

 int bookCount = dataEbookCollectionMapper.selectCount(new QueryWrapper<DataEbookCollectionBean>()
                .select(" DISTINCT data_id").lambda()
                .eq(DataEbookCollectionBean::getEbookCollectionRuid, eBookCollectionRuid)
                .in(unitRuidList.size() > 0, DataEbookCollectionBean::getEbookCollectionUnitRuid, unitRuidList)
        );

转换的查询语句：

SELECT COUNT( DISTINCT data_id ) 
FROM `data_ebook_collection` 
WHERE (ebook_collection_ruid = ? AND ebook_collection_unit_ruid IN  (?,?,?)