Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_24894 ( "Ch \u2116" text, "Channel" text, "Channel content" text, "Transmission" text, "Format" text, "Launch Date" text, "Licence" text )

### Question ###
How many launch dates are there for digital transmission?

### Accurate SQL ###

SELECT COUNT("Launch Date") FROM table_24894 WHERE "Transmission" = 'Digital'