查询表达式C＃（访问数据库）中的语法错误（缺少运算符）

Question

你好！我试图在Visual Basic c＃中连接4个表格形式的Access，但出现“查询表达式中的语法错误（缺少运算符）”，请您帮我吗？谢谢！

string query = "Select e.Denumire_Ech, e.Descriere_Ech, e.UnitateMasura, e.Pret_Vanzare, o.Cantitate_EchOf From ECHIPAMENTE e INNER JOIN OFERTE o ON e.Cod_Echipament = o.Cod_Echipament INNER JOIN CONTRACTE c ON c.Cod_Oferta = o.Cod_Oferta INNER JOIN FACTURI f ON f.Nr_Contract = c.Nr_Contract WHERE Nr_Contract='" + CB_Contract.Text + "'";

Answer 1

您有多个要联接的表，但未指定WHERE子句在哪个表上查找。

string query = "Select e.Denumire_Ech, e.Descriere_Ech, e.UnitateMasura, e.Pret_Vanzare, o.Cantitate_EchOf From ECHIPAMENTE e INNER JOIN OFERTE o ON e.Cod_Echipament = o.Cod_Echipament INNER JOIN CONTRACTE c ON c.Cod_Oferta = o.Cod_Oferta INNER JOIN FACTURI f ON f.Nr_Contract = c.Nr_Contract WHERE c.Nr_Contract='" + CB_Contract.Text + "'";

此外，您还应注意CB_Contract.Text中的SQL注入和异常字符，例如，如果有'字符，则sql将失败。