问题描述

求助大神 SQL怎么在C#里面用不了LIKE查询

请帮帮忙string select_sql;
string connect_sql = "Data source=.; initial catalog=project; integrated security=true";
select_sql = "use project select ISBN,BKNAME,AUTHOR,PUBLISHER,PRICE,CNUM,SNUM from book where @libname LIKE bkname";
SqlConnection sc = new SqlConnection(connect_sql);
SqlCommand cmd = new SqlCommand(select_sql, sc);
SqlParameter snoparam = new SqlParameter("@libname", textBox1.Text);
cmd.Parameters.Add(snoparam);
SqlDataAdapter da = new SqlDataAdapter();
// da.Fill(ds, "grde");
da.SelectCommand = cmd;
DataSet pro = new DataSet("project");
pro.Tables.Add("jy");
da.Fill(pro, "jy");
dataGridView1.DataSource = pro.Tables["jy"];
sc.Close();

解决方案

 select_sql = "use project select ISBN,BKNAME,AUTHOR,PUBLISHER,PRICE,CNUM,SNUM from book where @libname LIKE bkname";
->
select_sql = "select ISBN,BKNAME,AUTHOR,PUBLISHER from book where bkname LIKE '%@libname%'";

解决方案二：

LIKE后的要用到单引号或者通配符

解决方案三：

定义的sql查询字符串写的有问题，应改为
select_sql = "select ISBN,BKNAME,AUTHOR,PUBLISHER from book where bkname LIKE '@libname'"
bkname和@libname的位置要换一下，并加引号，bkname为对应sql里的子段名字，后者为引用的值