四、PostgreSQL常用数据类型（精简）

Posted 2023-04-05

参考技术A

备注：
（1）numeric 不指定长度，可以保留的整数位和小数位很大；
（2）numeric(6,4)表示精度（precision，所有数字位的个数）为6，标度（scale，小数点右边所有小数位的个数）为4，例如23.5141

备注：varchar不指定长度，可以存储最大长度（1GB）

备注：保留两位小数，超过位数采用四舍五入法进行截断

1. https://www.yiibai.com/postgresql/postgresql-datatypes.html

PostgreSQL JSON类型字段常用操作

原文链接

初始数据

insert into name_age values('"id":1,"name":"小明", "age":18');
insert into name_age values('"id":2,"name":"小明1", "age":17');
insert into name_age values('"id":3,"name":"小明3", "age":16');
insert into name_age values('"id":4,"name":"小明4", "age":20');
insert into name_age values('"id":5,"name":"小明5", "age":30');
insert into name_age values('"id":6,"name":"小明6", "age":10');
insert into name_age values('"id":7,"name":"小明7", "age":15');
insert into name_age values('"id":8,"name":"小明8", "age":35');
insert into name_age values('"id":9,"name":"小明9", "age":35');

Where

精确匹配

SELECT info||'"gender":"男"' as a,info||'"gender":"男"'::jsonb as b,info as c from name_age where (info->>'id')::int4 = 2;

---

SELECT info||'"gender":"男"' as a,info||'"gender":"男"'::jsonb as b,info as c from name_age where (info->>'name') = '小明4';

模糊匹配

select * from name_age where info #>> 'name' like '%明';

---

select * from name_age where (info->>'name') like '%4';

排序

select * from name_age order by info->'age' desc,info->'id' asc;
select * from name_age order by info->>'age' desc,info->'id' asc;
select * from name_age order by info->>'age' desc,info->>'id' asc;

修改

增加json字段

update name_age set info = info || '"gender":"男"'::jsonb  where (info->>'id')::int4 = 1;

删除json字段

update name_age set info = info-'gender' where  (info->>'id')::int4 = 1;

修改json字段值

update name_age set info = info || '"age":16'::jsonb  where (info->>'id')::int4 = 1;

分页

select * from name_age order by info->>'age' desc,info->>'id' asc  limit 2 offset 1;

• offset 从0开始