小编Jef*_*son的帖子

我有以下选择查询创建:

final DSLContext create = DSL.using(..., SQLDialect.POSTGRES);

create
 .select(DSL.field("identifier"), DSL.field("name"), 
         create.selectCount()
               .from(DSL.table("person"))
               .where(DSL.field("identifier").eq(DSL.field("personOuter.identifier")))
               .asField("count"))
 .from(DSL.table("person").as("personOuter"))

jOOQ生成以下查询:

select 
    identifier, 
    name, 
   (select count(*) 
    from person 
    where identifier = personOuter.identifier) as "count" 
from person as "personOuter"

查询应该是:

select 
    identifier, 
    name, 
   (select count(*) 
    from person 
    where identifier = personOuter.identifier) as "count" 
from person as personOuter

后一种查询在PostgreSQL中完美运行.表别名不应该用引号括起来.

这是一个错误吗？

(请注意,查询非常愚蠢.我正在玩jOOQ进行评估.)

以下"黑客"有效:

create
 .select(DSL.field("identifier"), DSL.field("name"), 
         create.selectCount()
               .from(DSL.table("person"))
               .where(DSL.field("identifier").eq(DSL.field("personOuter.identifier")))
               .asField("count"))
 .from("person as personOuter")

我有一份条件清单:

List<Condition> conditions = ...;

将这些条件组合(或组合)成新条件的最简单方法是什么？

Condition condition = and(conditions);

JOOQ是否具有实用功能？我同意这很容易写,但我宁愿不重新发明轮子.

jOOQ是否支持PostgreSQL数组函数和运算符？

array(select ... from ...)
array_length(array)
...

有关概述,请参见http://www.postgresql.org/docs/current/static/functions-array.html.

编辑

我在下面添加了一个示例查询.我还添加了查询来创建和填写表格,因此请尝试查询.

drop table if exists person_country;
drop table if exists person;
drop table if exists country;

create table person
(
    identifier      integer     not null,
    name            text        not null,

    primary key(identifier)
);
create table country
(
    identifier      integer     not null,
    name            text        not null,

    primary key(identifier)
);
create table person_country
(
    person_identifier   integer     not null,
    country_identifier  integer     not null,

    primary key(person_identifier, country_identifier),
    foreign key(person_identifier) references person,
    foreign key(country_identifier) references country …