50分SQL语句的问题，解释一下

来源：百度知道 编辑：UC知道 时间：2024/06/18 09:46:37
sql_str = "select plan_furnace.furnace_plan_no 炉订号,plan_furnace.z_macode 转炉物料编码,plan_furnace.d_macode 电炉物料编码,(select min(aufnr) from ay_interface_public.erptomes_produceorder_header where trim(plan_furnace.z_macode) = trim(plnbez) and to_char(gstrp,'yyyyMM') = '" + DateTime.Now.ToString("yyyyMM") + "') as 转炉生产订单号,(select min(aufnr) from ay_interface_public.erptomes_produceorder_header where trim(plan_furnace.d_macode) = trim(plnbez) and to_char(gstrp,'yyyyMM') = '" + DateTime.Now.ToString("yyyyMM") + "') as 电炉生产订单号,plan_wei 炉重 from plan_furnace,plan_zb where plan_furnace.plan_zb_no=plan_zb.zb_no and not exists(select distinct a.plan_zb_no from plan_furnace a where send_time is not null and a.plan_zb_no=plan_furnace.plan_zb_no)";
from plan_furnace,plan_zb where plan_furnace.plan_zb_no=plan_zb.zb_no and not exists(select distinct a.plan_zb_no from plan_furnace a where send_time is not null and a.plan_

分解一下,这是一个从数据库中取数,一句一句的分解:
1.这是一个变量
sql_str

2.查询语言标志
select

3.plan_furnace表中的炉订号
plan_furnace.furnace_plan_no 炉订号,

4.plan_furnace表中的转炉物料编码
plan_furnace.z_macode 转炉物料编码,

5.plan_furnace表中的电炉物料编码
plan_furnace.d_macode 电炉物料编码,

6.将ay_interface_public.erptomes_produceorder_header符合plan_furnace.z_macode及yyyyMM条件的最小aufnr返回
(select min(aufnr) from ay_interface_public.erptomes_produceorder_header where trim(plan_furnace.z_macode) = trim(plnbez) and to_char(gstrp,'yyyyMM') = '"

7.得到当前日期的yyyyMM,如200809
+ DateTime.Now.ToString("yyyyMM") + "') as 转炉生产订单号,

8.将ay_interface_public.erptomes_produceorder_header符合plan_furnace.z_macode及yyyyMM条件的最小aufnr返回
(select min(aufnr) from ay_interface_public.erptomes_produceorder_header where trim(plan_furnace.d_macode) = trim(plnbez) and to_char(gstrp,'yyyyMM') = '"

9.得到当前日期的yyyyMM