Table: mobile_carriers
Columns: carrier
standard
frequency
connection_speed
launch_date_dd_mm_yyyy

Question: What was the connection speed when launched on 07.06.2005?
SQL: SELECT "connection_speed" FROM mobile_carriers WHERE "launch_date_dd_mm_yyyy" = '07.06.2005'

Question: When the carrier is idc, what are the frequencies?
SQL: SELECT "frequency" FROM mobile_carriers WHERE "carrier" = 'IDC'

Question: When the launch date is 14.09.2005, and the frequency is 900mhz and 1800mhz, how many carriers are there?
SQL: SELECT COUNT("carrier") FROM mobile_carriers WHERE "frequency" = '900MHz and 1800MHz' AND "launch_date_dd_mm_yyyy" = '14.09.2005'

Question: How many standards are there, when the launch date was 17.04.2006?
SQL: SELECT COUNT("standard") FROM mobile_carriers WHERE "launch_date_dd_mm_yyyy" = '17.04.2006'