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 problems (problem_id VARCHAR, date_problem_reported INTEGER)

### Question ###
What are the ids of the problems which are reported before 1978-06-26?

### Accurate SQL ###

SELECT problem_id FROM problems WHERE date_problem_reported < "1978-06-26"