SQL开发知识：postgresql如何 删除重复数据

1.建表

/*
Navicat Premium Data Transfer

Source Server : localhost
Source Server Type : PostgreSQL
Source Server Version : 110012
Source Host : localhost:5432
Source Catalog : postgres
Source Schema : public

Target Server Type : PostgreSQL
Target Server Version : 110012
File Encoding : 65001

Date: 30/07/2021 10:10:04
*/

— —————————-
— Table structure for test
— —————————-
DROP TABLE IF EXISTS “public”.”test”;
CREATE TABLE “public”.”test” (
“id” int4 NOT NULL DEFAULT NULL,
“name” varchar(255) COLLATE “pg_catalog”.”default” DEFAULT NULL,
“age” int4 DEFAULT NULL
)
;

— —————————-
— Records of test
— —————————-
INSERT INTO “public”.”test” VALUES (1, ‘da’, 1);
INSERT INTO “public”.”test” VALUES (2, ‘da’, 12);
INSERT INTO “public”.”test” VALUES (3, ‘dd’, 80);
INSERT INTO “public”.”test” VALUES (4, ‘dd’, 80);
INSERT INTO “public”.”test” VALUES (5, ‘d1’, 13);

— —————————-
— Primary Key structure for table test
— —————————-
ALTER TABLE “public”.”test” ADD CONSTRAINT “test_pkey” PRIMARY KEY (“id”);