優化此慢速mysql查詢

Question

SELECT SUM( a.situacao =2 OR a.situacao =0 ) AS cotacoes, 
       SUM( a.situacao =1 ) AS n_publicar, 
       SUM( a.inicio <= NOW( ) AND DATE_ADD( a.inicio, INTERVAL a.duracao HOUR ) >= NOW( ) AND a.situacao =2 ) AS disputa, 
       SUM( a.inicio > NOW( ) AND a.situacao =2 ) AS agendados, 
       SUM( DATE_ADD( a.inicio, INTERVAL a.duracao HOUR ) <= NOW( ) AND a.situacao =2 AND a.id_vencedor = -2 ) AS analise, 
       SUM( a.prazoi > NOW( ) AND a.situacao =2 AND a.id_vencedor >0 ) AS aguardando_execucao, 
       SUM( a.situacao =0 ) AS cancelados, 
       SUM( DATE_ADD( a.inicio, INTERVAL a.duracao HOUR ) <= NOW( ) AND a.situacao =2 AND a.id_vencedor = -3 ) AS fracassados, 
       SUM( a.prazot < NOW( )  AND a.situacao =2 AND a.id_vencedor >0 AND ( b.id_avaliacao IS NULL  OR b.id_avaliacao =  '' ) ) AS avaliacao, 
       SUM( a.situacao =2 AND a.id_vencedor >0 AND a.prazot > NOW( )  AND a.prazoi <= NOW( ) ) AS execucao 
FROM leilao_pregoes a 
LEFT JOIN leilao_avaliacao b ON a.id_pregao = b.id_pregao AND b.situacao = 1
INNER JOIN leilao_edital c ON a.id_edital = c.id_edital 
WHERE c.id_comprador =1

我知道這可以改善...

Answer 1

我想知道在可行的情況下COUNT是否會更快。

主要的改進將是獲取列作為記錄：

cotacoes    123
n_publicar   456
...

SELECT 'cotacoes', SUM(...)
...
UNION SELECT 'n_publicar', SUM(...)
...

原因是條件部分排除，然后可以更好地利用連接。

另外，您也可以分別處理最慢的SELECT。 您可以執行並行查詢，將其拆分為子查詢。

Answer 2

LEFT JOIN leilao_avaliacao b ON a.id_pregao = b.id_pregao AND b.situacao = 1

leilao_avaliacao需要兩種順序的INDEX(id_pregao, situacao) 。

INNER JOIN leilao_edital c ON a.id_edital = c.id_edital
WHERE c.id_comprador =1

leilao_edital需要INDEX(id_comprador, id_edital)

為了進行進一步的討論，請提供SHOW CREATE TABLE並提供一些有關表的大小的提示。