Sql语句Java表示2个表和2个值（变量）

Question

我正在尝试执行以下操作并且它不接受它。

String sql_eco = "select * from orders where EmployeeID=" +e_ID + " and CustomerID ="' + cu_ID + "'";

从两个表和两个值（变量）中选择

Answer 1

尝试，假设CustomerID和EmployeeID都是Integer列类型

String sql_eco = "select * from orders where EmployeeID=" +e_ID + " and CustomerID =" + cu_ID;

Answer 2

试试这个：

String sql_eco = "select * +
                  from orders +
                  where EmployeeID=" +e_ID + " and CustomerID ='" + cu_ID + "'";   
                                                               ^                                                                         

Answer 3

使用它。你错放了“for CustomerId

String sql_eco = "select * from orders where EmployeeID=" +e_ID + " and CustomerID ='" + cu_ID + "'";

Answer 4

值变量你想说这样的话吗？

String sql_eco = "select * +
                  from orders +
                  where 1=1 ";
if(e_ID  != null) {
 sql_eco += " AND EmployeeID=" +e_ID ;
}
if(cu_ID  != null){
 sql_eco  += " and CustomerID ='" + cu_ID + "'";  
}

要改进此代码，您可以使用stringbuilder/stringbuffer