Question

System.Data.SqlClient.SqlException: '=' 附近有语法错误。

SqlCommand cmd = new SqlCommand("select ifmarriage from person_bistc where person_id=" + this.DropDownList3.Text, sqlconn);
this.TextBox2.Text = cmd.ExecuteScalar().ToString();

Answer 1

这样写容易出错，建议使用如下2种方法：
1.
String sql=String.Format("select ifmarriage from person_bistc where person_id='{0}'",this.DropDownList3.Text);

2.
String sql="select ifmarriage from person_bistc where person_id=@person_id";
SqlCommand cmd = new SqlCommand(sql, cn);
cmd.Parameters.AddWithValue("@person_id",this.DropDownList3.Text);

这2种写法，好处多多，特别是第二种

Answer 2

"select ifmarriage from person_bistc where person_id=" '+ this.DropDownList3.Text+"'"