想从SQL表中搜索布尔结果C＃(Would like a Boolean result from a SQL table search C#)

想从SQL表中搜索布尔结果C＃(Would like a Boolean result from a SQL table search C#)

我正在尝试使用C＃SQL搜索，然后获取关于是否找到该项目的布尔结果。 我有搜索语句工作但不是布尔结果部分。

EX：如果我有一个名为@Names的列的表，其名称为A，B，C，但我搜索名称D，如何或者我可以得到一个布尔结果返回并在布尔变量中保存false。

I am trying to use a C# SQL search and then get a Boolean result on whether or not the item was found. I have the search statement working but not the Boolean result portion.

EX: If i have a table with a column called @Names with the names, A,B,C but i search for Name D, how or can i get a Boolean result to come back and save false in a Boolean variable.

最满意答案

你可以尝试这种方法：

string query = @" select case when exists ( select 1 from MyTable where Name='D' -- This is the condition you are checking ) then 1 else 0 end"; bool exists; using(var command = new SqlCommand(query, connection)) { exists = Convert.ToBoolean(command.ExecuteScaler()); }

您现在可以使用ExecuteScalar方法，并将结果转换为bool以获取查询结果。

You can try this approach:

string query = @" select case when exists ( select 1 from MyTable where Name='D' -- This is the condition you are checking ) then 1 else 0 end"; bool exists; using(var command = new SqlCommand(query, connection)) { exists = Convert.ToBoolean(command.ExecuteScaler()); }

You can now use the ExecuteScalar method, and cast the result to bool for the result of your query.