Service

QueryWrapper<BdgSummaryApprovalVO> query = this.initQueryWrapper(qry, "bdg_bdg_apply_list");
int total =  bdgBudgetProjectMapper.querySummaryApprovalTotal(query);

Dao

// Constants 取自 package com.baomidou.mybatisplus.core.toolkit;
int querySummaryApprovalTotal(@Param(Constants.WRAPPER) QueryWrapper<BdgSummaryApprovalVO> query);

mapper.xml

    <select id="querySummaryApprovalTotal" resultType="int">
        select  count(bb.id)
        from bdg_budget_project bbp
        left join bdg_budget bb on bb.id = bbp.budget_id
        ${ ew.customSqlSegment }
    </select>