如果条件为真但我尝试建立内部联接,但它不起作用,我尝试了以下两种方法:
IF chat.tipo = 'vitima' THEN
INNER JOIN vitima ON vitima.id_vit = chat.id_tipo
ELSE
INNER JOIN terceiro ON terceiro.id_ter = chat.id_tipo
或
IF(chat.tipo = 'vitima',
INNER JOIN vitima ON vitima.id_vit = chat.id_tipo,
INNER JOIN terceiro ON terceiro.id_ter = chat.id_tipo)
但是两者都会出错,我想要的是,如果类型等于“ vitima”,则它在一个表中执行内部noin,否则在另一个表中执行
。完整查询:
SELECT ocorrencia.id_oco,
(SELECT GROUP_CONCAT(c.id_oco ORDER BY c.id_oco DESC) FROM ocorrencia as c WHERE c.id_sup_oco = ocorrencia.id_sup_oco) as grouped_ids,
ocorrencia.id_sup_oco,
chat.id_tipo,
suporte_oco.data_sup,
suporte_oco.placa_sup,
suporte_oco.sinistro_sup,
suporte_oco.prefixo_sup,
ocorrencia.id_emp_oco,
IF(chat.tipo = 'vitima', vitima.nome_vit, terceiro.nome_ter) as nome,
chat.tipo
FROM chat
INNER JOIN ocorrencia ON ocorrencia.id_oco = chat.id_oco_cha
INNER JOIN suporte_oco ON suporte_oco.id_sup = ocorrencia.id_sup_oco
IF chat.tipo = 'vitima'
INNER JOIN vitima ON vitima.id_vit = chat.id_tipo
ELSE
INNER JOIN terceiro ON terceiro.id_ter = chat.id_tipo
WHERE chat.id_user = '20' OR chat.id_user_req = '20' GROUP BY (chat.id_oco_cha) ORDER BY chat.data DESC
答案 0 :(得分:1)
您不能在join
中使用条件,可能更容易使用union
,例如:
select * from chat inner join vitima ON
union all
select * from chat inner join terceiro ON chat.tipo <> 'vitima' AND terceiro.id_ter = chat.id_tipo
我能想到的另一个变体是:
select *
from chat, vitima, terceiro
where
(chat.tipo = 'vitima' AND vitima.id_vit = chat.id_tipo)
OR
(chat.tipo <> 'vitima' AND terceiro.id_ter = chat.id_tipo)
答案 1 :(得分:1)
不完全正确,但是我认为这将非常接近您要尝试执行的操作:
LEFT JOIN vitima ON vitima.id_vit = chat.id_tipo AND chat.tipo = 'vitima'
LEFT JOIN terceiro ON terceiro.id_ter = chat.id_tipo AND chat.tipo != 'vitima'
...
WHERE (chat.tipo = 'vitima' AND vitima.id_vit IS NOT NULL)
OR (chat.tipo != 'vitima' AND terceiro.id_ter IS NOT NULL)
LEFT JOIN
条件将强制执行您的规则,而WHERE
条件将模拟并INNER JOIN
,因为它要求这些记录存在。
您发布的完整查询如下所示:
SELECT ocorrencia.id_oco,
(SELECT GROUP_CONCAT(c.id_oco ORDER BY c.id_oco DESC) FROM ocorrencia as c WHERE c.id_sup_oco = ocorrencia.id_sup_oco) as grouped_ids,
ocorrencia.id_sup_oco,
chat.id_tipo,
suporte_oco.data_sup,
suporte_oco.placa_sup,
suporte_oco.sinistro_sup,
suporte_oco.prefixo_sup,
ocorrencia.id_emp_oco,
IF(chat.tipo = 'vitima', vitima.nome_vit, terceiro.nome_ter) as nome,
chat.tipo
FROM chat
INNER JOIN ocorrencia ON ocorrencia.id_oco = chat.id_oco_cha
INNER JOIN suporte_oco ON suporte_oco.id_sup = ocorrencia.id_sup_oco
LEFT JOIN vitima ON vitima.id_vit = chat.id_tipo AND chat.tipo = 'vitima'
LEFT JOIN terceiro ON terceiro.id_ter = chat.id_tipo AND chat.tipo != 'vitima'
WHERE chat.id_user = '20' OR chat.id_user_req = '20'
AND (
(chat.tipo = 'vitima' AND vitima.id_vit IS NOT NULL)
OR (chat.tipo != 'vitima' AND terceiro.id_ter IS NOT NULL)
)
GROUP BY (chat.id_oco_cha) ORDER BY chat.data DESC