How to Count Number of Rows for Each Categorical Value

As an example, I will count number of rows (number of flights) for each airline carrier in this flight data.

From the header of CARRIER column, follow the column header menu like this.

This opens Summarize dialog with preview of resulting table with number of rows for each CARRIER column value.

Note that the numbers on this preview table is smaller than actual number of rows, since this preview table is created on a sampled table, so that it can be calculated quickly.

Just click Run to create the summarized table with actual number of rows.