SQL命令搜索

Question

SqlCommand cmd = new SqlCommand("select * from [Table] where Col1 like 
                      %@astr% or Col2 like %@astr% or Col3 like %@astr%)", con);        
cmd.Parameters.AddWithValue("@astr", st);

上面的命令出了什么问题？ 我收到了“@astr附近”的错误消息。

Answer 1

您必须在变量中指定通配符（%），在查询中删除通配符。

st = string.Format("%{0}%", st); // in case your search string don't have wild characters..
SqlCommand cmd = new SqlCommand("select * from [Table] where Col1 like 
                      %@astr% or Col2 like @astr or Col3 like @astr)", con);        
cmd.Parameters.AddWithValue("@astr", st);

Answer 2

搜索字符串周围的引号丢失，一个括号太多：

SqlCommand cmd = new SqlCommand(
  @"select * from [Table] 
    where Col1 like '%' || @astr || '%' 
       or Col2 like '%' || @astr || '%' 
       or Col3 like '%' || @astr || '%'", con);        

Answer 3

如果astr是一个字符串。你可以试试这个。

string astr = "ABC";
SqlCommand cmd = new SqlCommand("select * from [Table] where Col1 like %" + astr + "% or Col2 like %" + astr + "% or Col3 like %" + astr + "%", con); 
cmd.Parameters.AddWithValue("@astr", st);