Table: river_class_info
Columns: hr_no
hr_name
cr_no
lms_no
built
works
withdrawn

Question: What is the lowest cr number?
SQL: SELECT MIN("cr_no") FROM river_class_info

Question: When 2/1939 is the withdrawn when was it built?
SQL: SELECT "built" FROM river_class_info WHERE "withdrawn" = '2/1939'

Question: When river ness is the hr name what is the hr number?
SQL: SELECT "hr_no" FROM river_class_info WHERE "hr_name" = 'River Ness'

Question: When (river garry) is the hr name how many builts are there?
SQL: SELECT COUNT("built") FROM river_class_info WHERE "hr_name" = '(River Garry)'

Question: What is the highest cr number?
SQL: SELECT MAX("cr_no") FROM river_class_info

Question: When river ness is the hr name how many builts are there?
SQL: SELECT COUNT("built") FROM river_class_info WHERE "hr_name" = 'River Ness'