access数据库多个left join示例

代码：

/// <summary>

/// 分类检索 查询selectname

/// </summary>

public static DataTable GetSelectName_FLJS(string thing_type_id, string men_id, string gang_id, string mu_id, string ke_id, string shu_id)

{

    StringBuilder sb = new StringBuilder(string.Format(@"

        select sn.Sel_chiname as 中文名, sn.Sel_engname as 英文名, sn.Sel_latname as 学名,

        sn.Thing_id, sn.Sel_type, sn.Thing_shu_id, sn.Thing_pro_id, sn.Thing_area_id

                

        from (((((selectname sn

        left join shu s on sn.thing_shu_id=s.shu_id)

        left join ke k on s.ke_id=k.ke_id)

        left join mu m on m.mu_id=k.mu_id)

        left join gang g on g.gang_id=m.gang_id)

        left join men me on me.men_id=g.men_id)

        left join thing_type tt on tt.thing_type_id=me.thing_type_id



        where 1=1"));



    if (!string.IsNullOrWhiteSpace(thing_type_id)

        && int.Parse(thing_type_id) != Common.OptionAllVal)

    {

        sb.Append(string.Format(@" 

            and tt.thing_type_id={0}", strUtil.SqlClean(thing_type_id)));

    }



    if (!string.IsNullOrWhiteSpace(men_id)

        && int.Parse(men_id) != Common.OptionAllVal)

    {

        sb.Append(string.Format(@" 

            and me.men_id={0}", strUtil.SqlClean(men_id)));

    }



    if (!string.IsNullOrWhiteSpace(gang_id)

        && int.Parse(gang_id) != Common.OptionAllVal)

    {

        sb.Append(string.Format(@" 

            and g.gang_id={0}", strUtil.SqlClean(gang_id)));

    }



    if (!string.IsNullOrWhiteSpace(mu_id)

        && int.Parse(mu_id) != Common.OptionAllVal)

    {

        sb.Append(string.Format(@" 

            and m.mu_id={0}", strUtil.SqlClean(mu_id)));

    }



    if (!string.IsNullOrWhiteSpace(ke_id)

        && int.Parse(ke_id) != Common.OptionAllVal)

    {

        sb.Append(string.Format(@" 

            and k.ke_id={0}", strUtil.SqlClean(ke_id)));

    }



    if (!string.IsNullOrWhiteSpace(shu_id)

        && int.Parse(shu_id) != Common.OptionAllVal)

    {

        sb.Append(string.Format(@" 

            and s.shu_id={0}", strUtil.SqlClean(shu_id)));

    }



    sb.Append(" order by sn.Sel_chiname");



    return AccessHelper.DataTable(sb.ToString());

}

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