left day 156.
sql50.
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question 1= 1978. Employees Whose Manager Left the Company.
solution= select employee_id from employees where salary<30000 and manager_id not in (select employee_id from employees) order by employee_id;
approach=> subquerry written in 'where not in' will return whole row column for checking.
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q 2 => 1667. Fix Names in a Table
ans => select user_id,concat(upper(substr(name,1,1)),lower(substr(name,2,length(name) ) )) name from users order by user_id;
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q 3=>