多表联合查询，怎么提高查询性能。

[dys_198102]

SELECT dbo.order_detail.doc_no, dbo.Product_Master.Model, dbo.Product_Master.Color,
dbo.order_detail.qty * dbo.order_detail.unit_price AS total_price,
dbo.Product_Master.description, dbo.Product_Master.stop_date,
dbo.workflow_detail.Result, dbo.workflow_detail.wf_no, dbo.So_Master.so_no,
dbo.So_Master.customer_code, dbo.So_Master.customer_name,
dbo.So_Master.so_date, dbo.So_Master.sales, dbo.order_detail.unit_price,
dbo.So_Master.trans_fee, dbo.So_Master.ignore, dbo.So_Master.financial,
dbo.So_Master.payment1, dbo.So_Master.cartage, dbo.So_Master.curr,
dbo.So_Master.tax, dbo.So_Master.TOTALAMOUNT
FROM dbo.Customer_Master INNER JOIN
dbo.So_Master ON
dbo.Customer_Master.customer_code = dbo.So_Master.customer_code INNER JOIN
dbo.workflow_master INNER JOIN
dbo.workflow_detail ON
dbo.workflow_master.wf_no = dbo.workflow_detail.wf_no INNER JOIN
dbo.Product_Master INNER JOIN
dbo.order_detail ON dbo.Product_Master.Part_no = dbo.order_detail.part_no ON
dbo.workflow_master.doc_no = dbo.order_detail.doc_no ON
dbo.So_Master.so_no = dbo.order_detail.doc_no
这是我做的最基本的查询，求高手指点，提高其查询性能

[波导终结者]

你不用where限定任何条件？那这样的话，这么多表笛卡尔乘积，不慢才怪。只用到需要的数据来join，可以大大提高效率。

[xiaogug01]

最好加个条件能快点吧。

[samuellei]

1. 为连接字段添加索引
2. 注意表连接的先后顺序

[dys_198102]

if keyword <> "" then
SQLComm=SQLComm & " and (Scustomer_name like N'%" & keyword & "%' or so_no like '%" & keyword & "%')"
end if
if account <> "t" then
SQLComm = SQLComm & "and sales = '"& account &"' "
end if
if stype <> "t" then
SQLComm = SQLComm & "and Result='" & stype & "'"
end if
if Ignore_type = "N" then
SQLComm = SQLComm & " And ignore is null "
end if
if Financial_type = "N" then
SQLComm = SQLComm & " And financial is null "
end if
SQLComm = SQLComm & " Order By so_date Desc, so_no Desc"
if Request.Form <> "" then
set rsCate = DBConn.Execute(SQLComm)
else
set rsCate = DBConn.Execute("select so_no from [so_master] where 1 <> 1 ")
end if
我后面是有条件的。但还是很慢，大家帮忙把上边的sql优化一下

[wuyq11]

分区，设置相应的索引
建立主键

[dys_198102]

谁帮我优化一下，谢谢急啊。。。

[bychgh]

学习

[zw_548498]

做个视图不是更好吗，

[qq254242213]

dui

[iStringTheory]

你可以在sqlserver里面查看下执行计划，根据执行计划来优化

[wuzhicheng5]

1. 为连接字段添加索引
2. 注意表连接的先后顺序

支持

[林三一]

1. 为连接字段添加索引
2. 注意表连接的先后顺序

支持

[dys_198102]

还没用过索引，常用的多表联合查询的sql语句：
select table1.ID from table1 inner join table2 on table1.ID=table2.ID
where table2.col2='xxx'

改进后：
select a.ID from table1 a,
(select col1,ID from table2 where col2='xxx') b
where a.ID=b.ID
看看这个怎么按这个优化