Filtrando com HAVING

Melhorando o Desempenho de Consultas no SQL Server

Dean Smith

Founder, Atamai Analytics

Ordem de processamento do HAVING

1.  FROM

4.  WHERE

6.  HAVING

7.  SELECT

Agrupando com filtro WHERE na linha

SELECT Team, 
    SUM(TotalPoints) AS TotalSGTeamPoints
FROM PlayerStats
WHERE Position = 'SG'
GROUP BY Team

Team	TotalSGTeamPoints
ATL	2034
BOS	1606
BRK	2126
CHI	2905
CHO	2661
CLE	2489
...	...

Filtrando linhas com HAVING

SELECT Team, 
    SUM(TotalPoints) AS TotalSGTeamPoints
FROM PlayerStats
WHERE Position = 'SG'
GROUP BY Team

SELECT Team, 
    SUM(TotalPoints) AS TotalSGTeamPoints
FROM PlayerStats
--WHERE Position = 'SG'
GROUP BY Team, Position
HAVING Position = 'SG'

Não use HAVING para filtrar linhas individuais ou não agrupadas

Team	TotalSGTeamPoints
ATL	2034
BOS	1606
BRK	2126
CHI	2905
CHO	2661
CLE	2489
...	...

Agregando por grupo

SELECT 
    Team, 
    SUM(DRebound+ORebound) AS TotRebounds,
    SUM(DRebound) AS TotDef,
    SUM(ORebound) AS TotOff
FROM PlayerStats
GROUP BY Team;

Team	TotRebounds	TotDef	TotOff
ATL	3436	2693	743
BOS	3645	2878	767
BRK	3644	2852	792
CHI	3663	2873	790
CHO	3728	2901	827
CLE	3455	2761	694
...	...	...	...

Filtrando grupos com WHERE

SELECT 
    Team, 
    SUM(DRebound+ORebound) AS TotRebounds,
    SUM(DRebound) AS TotDef,
    SUM(ORebound) AS TotOff
FROM PlayerStats
WHERE ORebound >= 1000
GROUP BY Team;

Use WHERE para filtrar linhas individuais e HAVING para um filtro numérico em linhas agrupadas

Team	TotRebounds	TotDef	TotOff

Sem função de agregação

SELECT 
    Team, 
    SUM(DRebound+ORebound) AS TotRebounds,
    SUM(DRebound) AS TotDef,
    SUM(ORebound) AS TotOff
FROM PlayerStats
GROUP BY Team
HAVING ORebound >= 1000;

Aplique o filtro HAVING a uma coluna numérica usando uma função de agregação

------------------------------------------------
-- ERROR
Column 'PlayerStats.ORebound' is invalid in the 
HAVING clause because it is not contained in 
either an aggregate function or the GROUP BY 
clause.

Com função de agregação

SELECT 
    Team, 
    SUM(DRebound+ORebound) AS TotRebounds,
    SUM(DRebound) AS TotDef,
    SUM(ORebound) AS TotalOff
FROM PlayerStats
GROUP BY Team
    -- aggregate function SUM()
HAVING SUM(ORebound) >= 1000;

Team	TotRebounds	TotDef	TotOff
OKC	3695	2671	1024

Resumo

Não use HAVING para filtrar linhas individuais ou não agrupadas
Use WHERE para filtrar linhas individuais e HAVING para filtro numérico em linhas agrupadas
HAVING só pode ser aplicado a uma coluna numérica em um filtro com função de agregação

Vamos praticar!

Melhorando o Desempenho de Consultas no SQL Server