我遇到了带有多个连接的复杂查询的问题。运行EXPLAIN时：
查询
explain
select ud.id from user_detail ud
cross join ticket t
cross join guest_list gl
cross join event e
cross join venue v
where t.guest_list = gl.id and gl.event = e.id and e.venue = v.id
and (ud.account = 10 or ud.venue = 10 or ud.event = 10 or ud.guest_list = 10 or t.reference_user = 10 and (ud.guest_list=t.guest_list or ud.event = gl.event or ud.venue = e.venue or ud.account = v.account) and (t.guest_list = 10))
我明白了：
id, select_type, table, type, rows, extra
1, SIMPLE, v, index, 2, "Using index"
1, SIMPLE, e, ref, 2, "Using where; using index"
1, SIMPLE, gl, ref, 1, "Using where; using index"
1, SIMPLE, t, ref, 418, "Using where"
1, SIMPLE, ud, ALL, 44028, "Using where; Using join buffer"
数据模型如下：
帐户＆lt; 1- ＆gt;地点＆lt; 1 - ＆gt;事件＆lt; 1- ＆gt;访客列表＆lt; 1 - ＆gt;票 UserDetail有一个帐户，地点，事件或访客列表作为父母。
我正在尝试使用此查询来获取具有特定帐户/地点/事件/访客列表之一作为父亲的所有UserDetail，或者具有访客列表作为父亲具有故障单的故障单将reference_user字段设置为特定用户。
Hibernate条件
public List<UserDetail> listUserDetails(final Collection<UserDetailNode> anyOfNodes, final User orTicketReferenceUser, final Collection<GuestList> andAnyOfGuestlistsForTicketReferenceUser, final Collection<User> anyOfUsers, final Date fromLastModificationDate, final Date toLastModificationDate, final Boolean deletedNodes, final Boolean deletedUsers, final Boolean deletedUserDetails) {
final CriteriaBuilder cb = entityManager.getCriteriaBuilder();
final CriteriaQuery<UserDetail> cq = cb.createQuery(UserDetail.class);
final Root<UserDetail> userDetail = cq.from(UserDetail.class);
Predicate criteria = cb.conjunction();
if (anyOfNodes != null || orTicketReferenceUser != null) {
Predicate subCriteria = cb.disjunction();
if (anyOfNodes != null) {
Predicate anyOfNodesCriteria = cb.disjunction();
Collection<Account> anyOfAccounts = null;
Collection<Venue> anyOfVenues = null;
Collection<Event> anyOfEvents = null;
Collection<GuestList> anyOfGuestLists = null;
final Set<UserDetailNode> anyOfNodesWithParents = new HashSet<UserDetailNode>();
for (UserDetailNode node : anyOfNodes) {
while (node != null) {
anyOfNodesWithParents.add(node);
node = node.getParentNode();
}
}
for (final UserDetailNode node : anyOfNodesWithParents) {
if (node instanceof Account) {
if (anyOfAccounts == null) anyOfAccounts = new ArrayList<Account>();
anyOfAccounts.add((Account)node);
}
else if (node instanceof Venue) {
if (anyOfVenues == null) anyOfVenues = new ArrayList<Venue>();
anyOfVenues.add((Venue)node);
}
else if (node instanceof Event) {
if (anyOfEvents == null) anyOfEvents = new ArrayList<Event>();
anyOfEvents.add((Event)node);
}
else if (node instanceof GuestList) {
if (anyOfGuestLists == null) anyOfGuestLists = new ArrayList<GuestList>();
anyOfGuestLists.add((GuestList)node);
}
}
if (anyOfAccounts != null) anyOfNodesCriteria = cb.or(anyOfNodesCriteria, cb.or(userDetail.get("account").in(anyOfAccounts)));
if (anyOfVenues != null) anyOfNodesCriteria = cb.or(anyOfNodesCriteria, cb.or(userDetail.get("venue").in(anyOfVenues)));
if (anyOfEvents != null) anyOfNodesCriteria = cb.or(anyOfNodesCriteria, cb.or(userDetail.get("event").in(anyOfEvents)));
if (anyOfGuestLists != null) anyOfNodesCriteria = cb.or(anyOfNodesCriteria, cb.or(userDetail.get("guestList").in(anyOfGuestLists)));
subCriteria = cb.or(subCriteria, anyOfNodesCriteria);
}
if (orTicketReferenceUser != null && (andAnyOfGuestlistsForTicketReferenceUser == null || !andAnyOfGuestlistsForTicketReferenceUser.isEmpty())) {
final Root<Ticket> ticket = cq.from(Ticket.class);
Predicate ticketCriteria = cb.equal(ticket.get("referenceUser"), orTicketReferenceUser);
ticketCriteria = cb.and(ticketCriteria, cb.or(cb.equal(userDetail.get("guestList"), ticket.get("guestList")), cb.equal(userDetail.get("event"), ticket.get("guestList").get("event")), cb.equal(userDetail.get("venue"), ticket.get("guestList").get("event").get("venue")), cb.equal(userDetail.get("account"), ticket.get("guestList").get("event").get("venue").get("account"))));
if (andAnyOfGuestlistsForTicketReferenceUser != null) ticketCriteria = cb.and(ticketCriteria, ticket.get("guestList").in(andAnyOfGuestlistsForTicketReferenceUser));
subCriteria = cb.or(subCriteria, ticketCriteria);
}
criteria = cb.and(criteria, subCriteria);
}
if (anyOfUsers != null) {
if (anyOfUsers.isEmpty()) return new ArrayList<UserDetail>();
criteria = cb.and(criteria, userDetail.get("user").in(anyOfUsers));
}
if (fromLastModificationDate != null) criteria = cb.and(criteria, cb.greaterThanOrEqualTo(userDetail.<Date>get("lastModificationDate"), fromLastModificationDate));
if (toLastModificationDate != null) criteria = cb.and(criteria, cb.lessThanOrEqualTo(userDetail.<Date>get("lastModificationDate"), toLastModificationDate));
cq.select(userDetail).distinct(true).where(criteria);
return entityManager.createQuery(cq).getResultList();
}
从我可以看到的最后一行是问题，但我该如何解决这个问题？这个查询是由hibernate自动生成的，所以我不确定我能改变它多少。
答案 0 :(得分：1)
你过度使用交叉连接笛卡尔连接没有意义......你实际上在寻找什么。由于您的“OR”子句都基于此值10，但随后通过guest_list id对票证表进行隐式连接 - 最后需要t.guest_list = 10？
由于您的所有内部联接也在查看与联接结果具有相同值的原始用户详细信息表。您的踢球者是FINAL“AND”专门寻找guest_list = 10.我会立即从此开始作为基础和OR其他人......我可能会考虑以下内容：
select STRAIGHT_JOIN
ud.id
from
ticket t
JOIN user_detail ud
ON t.guest_list = ud.guest_list
where
t.guest_list = 10
AND ( ud.account = 10
or ud.venue = 10
or ud.event = 10 )
你引用了一个“Reference_User = 10”，但那个上下文是什么......就像一个用户细节有一个客人？并且该访客可以与相同的用户详细事件/地点/帐户相关联？
通过提供一些细节样本，澄清你希望获得的内容将会让你更进一步......