Question

Could someone give an answer to the following please?

Statement statement;

string sql;

sql = "SELECT gender FROM people WHERE gender = 'M' ";

results = statement.executeQuery(sql);

What kind of formatting do I have to do to represent ‘M’ in my string SQL query?

Notes: gender is either ‘M’ or ‘F’ and I want to return all rows that are of gender ‘M’.

Answer 1

'M' is the correct way to specify a value for a VARCHAR column if you write the query manually.

But a better way is usually to use a prepared statement:

stmt = connect.prepareStatement("SELECT gender FROM people WHERE gender = ?");
stmt.setString( 1, "M" );

The advantage of this approach is that JDBC will automatically convert the parameter for you, escape it properly, etc.

For example, your code will become much more complex for people’s names after you tried to add D'Angelo (common Italian name) to your database.