无法弄清楚如何在C＃中的查询表达式错误中修复语法错误（缺少运算符）

Question

I'm having an issue with an error written above and cannot find a exact way to fix it.

OleDbDataAdapter dataAdapter = new OleDbDataAdapter("Select count(*) from [contractors$] where " + category + " like '*@name*'", eh.Connection);
dataAdapter.SelectCommand.Parameters.Add("@name", OleDbType.VarChar).Value = "*" + name + "*";
OleDbCommand command = dataAdapter.SelectCommand;
OleDbDataReader reader = command.ExecuteReader();

The exact error is..

Syntax error (missing operator) in query expression 'like ' @name ''.

I've also already looked for solutions to this problem and have attempted to adapt them to try to get this work work, but with no luck(the one above was one of the attempts)

Much thanks in advance!

Ok, so I have now change the code to this..

OleDbDataAdapter dataAdapter = new OleDbDataAdapter("Select count(*) from `contractors$` where " + category + " LIKE @name", eh.Connection);
dataAdapter.SelectCommand.Parameters.Add("@name", OleDbType.VarChar).Value = "%" + name + "%";
OleDbCommand command = dataAdapter.SelectCommand;
OleDbDataReader reader = command.ExecuteReader();

But I am still getting the same error.

Answer 1

A parameter cannot be contained inside an SQL string literal. Use concatenation to build the string:

"... LIKE ('%' + @name + '%') ..."

Update

It seems that the value of category was null or empty, creating an invalid SQL statement:

 Select count(*) from [contractors$] where like '@name'
                                         ^^^ no category here