postgresql常用語句

最近接觸了pgsql,由於是關於將sqlserver遷移到pgsql過程中，在開發過程中，遇到的一些關於pgsql語句簡單實用語句，供初學者借鑒

1.自增

CREATE SEQUENCE public.tablename_id_seq
    INCREMENT 1
    START 1
    MINVALUE 1
    MAXVALUE 9223372036854775807
    CACHE 1;

 

2.大寫改小寫

ALTER TABLE "public"."tableName" RENAME COLUMN  "UnShared" To "unshared";

 

3.表明注釋

COMMENT ON TABLE "public"."tableName" IS '工資等級（績效、薪資等）';

 

4.創建表帶有索引自增

CREATE TABLE "public"."tableName" (
"id" serial PRIMARY KEY,
"minvalue" float8,
"maxvalue" float8
)
;

 

5.添加主鍵

ALTER TABLE "public"."tableName" 
ADD PRIMARY KEY ("id");

 

6.強制加自增(這個有借鑒別人寫的)

ALTER TABLE tablename ALTER COLUMN id SET DEFAULT null;
DROP SEQUENCE IF EXISTS tablename_id_seq;
-- 這里的 id_max 即 id 目前的最大值，可通過 “SELECT MAX(id) FROM tablename” 得到
-- CREATE SEQUENCE tablename_id_seq START WITH id_max;
-- SELECT MAX(id) FROM tablename
-- SELECT MAX(id) FROM tablename
CREATE SEQUENCE tablename_id_seq START WITH 38;
ALTER TABLE tablename ALTER COLUMN id SET DEFAULT nextval('tablename_id_seq'::regclass);

 

7.主鍵自增重新設置

SELECT setval('"tablename_id_seq"', (SELECT MAX("id") FROM "tablename"));

 

8.添加字段

ALTER TABLE "public"."tableName" ADD COLUMN "code" varchar(255);

 

9. 設置不能為空

ALTER TABLE "public"."tableName" ALTER COLUMN "code" SET NOT NULL;

 

10.設置唯一鍵

alter table "public"."tableName" add constraint "unique_code_sid" unique ("code");

 

 11.設置一個主鍵是int8（長度64）的自增主鍵

CREATE TABLE "public"."tableName" (
  "id" int8 PRIMARY KEY,
  "minvalue" float8,
  "maxvalue" float8
)
;

CREATE SEQUENCE tableName_id_seq 
    START WITH 1 
    INCREMENT BY 1 
    NO MINVALUE 
    NO MAXVALUE 
    CACHE 1; 
    
ALTER TABLE "public"."tableName" ALTER COLUMN id SET DEFAULT nextval('tableName_id_seq'::regclass);

 

12.刪除主鍵

alter table tableName drop constraint tableName_pkey;

 

13.添加復合主鍵

ALTER TABLE "tableName" 
  ADD PRIMARY KEY ("jsid","peid");

 

14.修改表字段類型長度（沒有改變類型）

alter table skypayitemobjs alter column  remark set data TYPE VARCHAR(5000);

 

15.表字段名備注

-- 表字段備注
COMMENT ON    column      suggest.id        is    '主鍵';

 

16.把int4類的主鍵改成int8

ALTER TABLE "public"."tableName" 
  ALTER COLUMN "id" TYPE int8 USING "id"::int8;

 17.建表時，主鍵int8自增

"id" bigserial PRIMARY KEY

18.創建默認時間

"modify_time" timestamp(6) default now()