【SqlServer】【问题收集】必须声明标量变量

2023-02-15 15:40:59

1 问题概述

在DAL层，通过标量给变量赋值时，出现如下异常

我们来看看在数据访问层的SQL语句：

//根据EmployeeName条件获取数据
        public DataTable GetEmployeeToTable(string EmployeeName)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("SELECT EmployeeID,EmployeeName,EmployeeMajor, EmployeeDepartment,EmployeeTel,EmployeeEmail, EmployeeJiGuan,EmployeeAddress,EmployeePosition,EmployeeBirthday ");
            strSql.Append(" WHERE EmployeeName=@EmployeeName ");
            SqlParameter[] parameters = {
                    new SqlParameter("@EmployeeName",SqlDbType.VarChar,50)
            };
            parameters[0].Value = EmployeeName;

            return DbHelperSQL.GetDataTable(strSql.ToString());
        }

2 问题分析与解决

2.1 问题分析

变量参数未传递进去

2.2 问题解决

将参数传递进去即可

public DataTable GetEmployeeToTable(string EmployeeName)
{
StringBuilder strSql = new StringBuilder();
strSql.Append("SELECT EmployeeID,EmployeeName,EmployeeMajor, EmployeeDepartment,EmployeeTel,EmployeeEmail, EmployeeJiGuan,EmployeeAddress,EmployeePosition,EmployeeBirthday ");
strSql.Append(" WHERE EmployeeName=@EmployeeName ");
SqlParameter[] parameters = {
new SqlParameter("@EmployeeName",SqlDbType.VarChar,50)
};
parameters[0].Value = EmployeeName;
return DbHelperSQL.Query(strSql.ToString(), parameters).Tables[0];
}