Here is how you can find the number of rows in a table.
Option 1. Find number of rows based on column value
SELECT count(*) FROM TableName where ColumnName = 'Guest';
Option 2. Use column name to count rows
SELECT count(ColumnName) FROM TableName;
Option 3. Use column name to count rows and specify column value
SELECT count(ColumnName) FROM TableName where ColumnName = 'Guest';