Category "correlated-subquery"

SQLite impute missing values by mean for every group

I have an SQLite table as shown below. students grades Nick 34 Nick 42 Nick 86 Nick Null John 38 John 12 John 74 John Null Colin 87 Colin 23 Colin 46 Colin 42

Querying pivot table to return a list of referred rows

I have these 6 tables and query which returns everything I want, but I want to add a new pivot table, so I can get a list of rows linked to it. Query: SELECT DI

SQL ZOO List each continent and the name of the country that comes first alphabetically

Im confused why it could not be Select x.continent, x.name From world x Where x.name <= ALL (select y.name from world y where x.name=y.name) ORDER BY name