If this SQL query is run in SQL Developer, will it work or not?

Without the actual SQL query text, it is impossible to definitively say whether it will work in SQL Developer or not. SQL Developer is a tool for working with Oracle databases, and it supports the SQL dialect specific to Oracle. If the query is written using syntax or functions specific to other DBMSs (e.g., PostgreSQL, MySQL), it is likely not to work without modifications.

To answer precisely, one needs to check:

• Is Oracle SQL syntax used?
• Are there functions or constructs in the query that are absent in Oracle?
• Is the query structure correct and free of syntax errors.

If you provide the query itself, a specific answer can be given.