c＃ - 如何解决from子句中的语法错误 [英] c# - How do I solve syntax error in from clause

问题描述

我的代码是：

MY CODE IS :

string query="select DISPATCH.Bill_No, NWTHAN.Quality, NWTHAN.Than_No, NWTHAN.Length, NWTHAN.Weight, NWTHAN.Tobaleno "+
                           "from DISPATCH , BALES , NWTHAN"+
                           "where DISPATCH.Bill_no='" + comboBox1.SelectedValue.ToString() + "' and BALES.Bill_No=DISPATCH.Bill_no and NWTHAN.Tobaleno=BALES.Bale_No" +
                            "order by NWTHAN.Than_No";

帮助我!!!

HELP ME !!!

推荐答案

你有两个问题：

1.你的代码很宽泛n到SQL注入...永远不要使用字符串连接来创建查询，使用参数化查询！

2.你不要在查询的各个部分之间添加空格......

这个：

You have two problems:
1. Your code is wide open to SQL injection...Never use string concatenation to create queries, use parametrized queries!
2. You do not add spaces between the parts of the query...
This:

"from DISPATCH , BALES , NWTHAN"+
"where DISPATCH.Bill_no='"

等于他：

Is equal to his:

"from DISPATCH , BALES , NWTHANwhere DISPATCH.Bill_no='"

你可以看到最后一个和之间没有空格其中 ...

您在订单上的颜色与相同...

As you can see no space between the last able and the where...
You have the very same at the order by...

1.我看到的第一个错误是你忘了在之前添加WHERE子句，并且在order by之前添加空格。



2.所以你应该像这样更改你的SQL：

1.The first error that I saw is that you forgot to let a space before to add "WHERE" clause, ans also before "order by".

2.So you should change your SQL like this:

string query="select DISPATCH.Bill_No, NWTHAN.Quality, NWTHAN.Than_No, NWTHAN.Length, NWTHAN.Weight, NWTHAN.Tobaleno "+
                           "from DISPATCH , BALES , NWTHAN "+ //Here was the problem!
                           "where DISPATCH.Bill_no='" + comboBox1.SelectedValue.ToString() + "' and BALES.Bill_No=DISPATCH.Bill_no and NWTHAN.Tobaleno=BALES.Bale_No " //Also here a similar problem! 
                            +"order by NWTHAN.Than_No";

string query="select DISPATCH.Bill_No, NWTHAN.Quality, NWTHAN.Than_No, NWTHAN.Length, NWTHAN.Weight, NWTHAN.Tobaleno "+
                           "from DISPATCH , BALES , NWTHAN"+
                           " where DISPATCH.Bill_no='" + comboBox1.SelectedValue.ToString() + "' and BALES.Bill_No=DISPATCH.Bill_no and NWTHAN.Tobaleno=BALES.Bale_No" +
                            " order by NWTHAN.Than_No";

只需在where和order by子句之前添加空格。你的查询运行正常。

just add space before where and order by clause. your query will run fine.

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