PostgreSQL 使用数组类型

　　为啥要用到数组类型呢？因为ES支持数组类型，为了迁移遍历，所以也支持数组类型。

select docid,authors from search_doc_new_ic where authors @>'{"惠普"}' limit 10;
docid                           |authors        |
--------------------------------+---------------+
cc88a182e84f4ab2a976abe1cbba0b41|{王玮嘉,惠普,黄波,环保Ⅱ}|
c3826da7a322490296ec9c5901ba353a|{王玮嘉,惠普,黄波}    |
fc4f63dec47b4facb8216d8b29d9918a|{王玮嘉,惠普,黄波}    |
863afb11385848c9a8a7c5df51024532|{王玮嘉,惠普,黄波,环保Ⅱ}|
fdc0562295304045b5c7ce940f96d56b|{王玮嘉,惠普,黄波,环保Ⅱ}|
6073e0de9b2747359c9b02e9bf0a9c2b|{王玮嘉,惠普,黄波}    |
facc9518c75148da8b079fde64f47691|{王玮嘉,惠普,黄波}    |
7c587a6337aa40c3acdbe7e363575317|{王玮嘉,惠普,黄波}    |
dcf807b2b0cc477ca7919cc41d9f5331|{王玮嘉,惠普,黄波}    |
631c4dd57afa40a694be1720e1b4a865|{王玮嘉,惠普,黄波}    |

SELECT * FROM sal_emp;
name |pay_by_quarter           |schedule                                 |
-----+-------------------------+-----------------------------------------+
Bill |{10000,10000,10000,10000}|{{meeting,lunch},{training,presentation}}|
Carol|{20000,25000,25000,25000}|{{breakfast,consulting},{meeting,lunch}} |

SELECT * FROM sal_emp where 15000 < any (pay_by_quarter); -- 查询pay_by_quarter数组中任何一个元素都大于15000
name |pay_by_quarter           |schedule                                |
-----+-------------------------+----------------------------------------+
Carol|{20000,25000,25000,25000}|{{breakfast,consulting},{meeting,lunch}}|

SELECT * FROM sal_emp where 22500 > ALL (pay_by_quarter); -- 查询pay_by_quarter数组中任何一个元素都小于22500
name|pay_by_quarter           |schedule                                 |
----+-------------------------+-----------------------------------------+
Bill|{10000,10000,10000,10000}|{{meeting,lunch},{training,presentation}}|

SELECT * FROM sal_emp where array_to_string(schedule,',') like '%sult%';   -- 数组模糊查询
name |pay_by_quarter           |schedule                                |
-----+-------------------------+----------------------------------------+
Carol|{20000,25000,25000,25000}|{{breakfast,consulting},{meeting,lunch}}|

访问JSON中的数组 

create table test_ft(id int4,arry VARCHAR[],content1 jsonb,body text);
insert into test_ft values(1,ARRAY [ 'x', 'y' ],'{
"guid": "9c36adc1-7fb5-4d5b-83b4-90356a46balabala",
"name": "james",
"is_active": true,
"company": "Oracle",
"address": "178 Howard Place, Gulf, Washington, 702",
"registered": "2009-11-07T08:53:22 +08:00",
"latitude": 19.793713,
"longitude": 86.513373,
"tags": [
"enim",
"aliquip",
"qui"
]}','postgresql支持两种json数据类型：json和jsonb，而两者唯一的区别在于效率,json是对输入的完整拷贝，使用时再去解析，所以它会保留输入的空格，重复键以及顺序等。而jsonb是解析输入后保存的二进制，它在解析时会删除不必要的空格和重复的键，顺序和输入可能也不相同。使用时不用再次解析。两者对重复键的处理都是保留最后一个键值对。效率的差别：json类型存储快，使用慢，jsonb类型存储稍慢，使用较快。');

select id,arry, content1->'name',substr(body,1,100) from test_ft t
where t.arry @>'{"x"}' 
and t.content1 @>'{"name":"james"}' and t.content1->'tags'->>1='aliquip'   -- 访问content1 JSON中tags数组元素的第一个值

 java到pg array的映射参见https://www.2ndquadrant.com/en/blog/using-java-arrays-to-insert-retrieve-update-postgresql-arrays/

https://www.postgresql.org/docs/current/functions-array.html