How to Write SQL Subqueries

Hi Hui! Thanks for reaching out. Please accept my apologies for the delayed response. Can you please support your question with a screenshot?  For example, do you mean that the icon for executing the entire code has greyed out? If that's the case, then you can retry by using the keyboard combination Ctrl + Shift + Enter. Looking forward to your answer.
Best,
Martin

Hello Hui. Have you tried SELECT statements? SQL subqueries are most frequently used with the Select statement. For example:

SELECT column_name FROM table_name   WHERE column_name expression operator    ( SELECT column_name  from table_name WHERE ... ); 

Could you additionally also attach a screenshot? Would be more than glad to take a look at the code