Aliasing - team BMI
A basketball statistician would like to know the average Body Mass Index (BMI) per NBA team, in particular, any team with an average BMI of 25 or more. To include Team in the query, you will need to join the Players table to the PlayerStats table. The query will require aliasing to:
- Easily identify joined tables and associated columns.
- Identify sub-queries.
- Avoid ambiguity in column names.
- Identify new columns.
Este exercício faz parte do curso
Improving Query Performance in SQL Server
Instruções do exercício
- Alias the new average BMI column as
AvgTeamBMI. - Alias the
PlayerStatstable asps. - Alias the sub-query as
p. - The
PlayerStatstable and sub-query are joining on the columnPlayerName. Add the aliases to the joiningPlayerNamecolumns.
Exercício interativo prático
Experimente este exercício completando este código de exemplo.
SELECT Team,
ROUND(AVG(BMI),2) AS ___ -- Alias the new column
FROM PlayerStats ___ ___ -- Alias PlayerStats table
INNER JOIN
(SELECT PlayerName, Country,
Weight_kg/SQUARE(Height_cm/100) BMI
FROM Players) ___ ___ -- Alias the sub-query
-- Alias the joining columns
ON ___.PlayerName = ___.PlayerName
GROUP BY Team
HAVING AVG(BMI) >= 25;