`card` INT(10) UNSIGNED NOT NULL, PRIMARY KEY (`id`) ); #图书 CREATE TABLE IF NOT EXISTS `book` ( `bookid` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `card` INT(10) UNSIGNED NOT NULL, PRIMARY KEY (`bookid`) ); #向分类表中添加20条记录 INSERT INTO type(card) VALUES(...
selectempid,keyask,value::textascardidfrom(selectempid,row_to_json(row(cardid,cardid2,cardid3,cardid4))asnfromemployee t )asrjoinlateral json_each_text(r.n)on(valueisnotnullandvalue!='') 6.不支持+=,不支持++ 7.列不存在则添加 ALTER TABLE table1 ADD if not exists name text; 8.用a...
CREATE DATABASE [IF NOT EXISTS] DBNAME [CHARACTER SET 'CHAR_NAME'] [COLLATE 'COLL_NAME'] 修改:ALTER 删除:DROP 创建一张新表: CRTATE TABLE [IF NOT EXISTS] TBNAME(col_name col_definition,...) 例: mysql> create table user( id int primary key auto_increment not null, uname varchar(20...
CREATEORREPLACEFUNCTIONcreatetable_urllist_withdate()RETURNSvarcharAS$BODY$declaretableNameWithDatevarchar; tableCreateSQLvarchar; currentDatevarchar;BEGINSELECTINTOcurrentDate to_char(current_date,'yyyymmdd'); tableNameWithDate:='tb_url_list_'||currentDate;ifnotexists(select1frompg_tableswheretablename=...
使用ALTER TABLE 语句来添加新字段。以下是一个示例 SQL 语句: sql ALTER TABLE employees ADD COLUMN email VARCHAR(255); 这条语句会将一个名为 email 的新字段添加到 employees 表中,数据类型为 VARCHAR(255)。 验证字段是否成功添加到表中: 你可以通过查询表的结构来验证新字段是否已经成功添加。在 PostgreS...
...;修改表中的字段名（将key1修改为key2）alter table tablename rename key1 to key2;表中新增字段 alter table tablename add key1 character varying not null;修改表名 alter table "tablename" rename to "new_tablename";删除表中某个字段 alter table tablename drop column if exists key1;
1 ALTER TABLE tablename ALTER COLUMN id SET DEFAULT null;2 DROP SEQUENCE IF EXISTS tablename_id_seq;3 -- 这里的 id_max 即 id 目前的最大值,可通过 “SELECT MAX(id) FROM tablename” 得到4 -- CREATE SEQUENCE tablename_id_seq START WITH id_max;5 -- SELECT MAX(id) FROM tablename6 ...
ALTERTABLEuser_tbl RENAME COLUMN signup_date TO signup; --删除栏位 ALTERTABLEuser_tblDROPCOLUMN email; --表格更名 ALTERTABLEuser_tbl RENAME TO backup_tbl; --删除表格 DROPTABLEIF EXISTS backup_tbl; 1. 2. 3. 4. 5. 6. 7. 8.
PG数据库和应用之间常见的部件有连接池、负载平衡组件、路由、防火墙等。我们常常不在意或者认为涉及的网络...
DROP TABLE IF EXISTS "public"."BASE_User"; CREATE TABLE "public"."BASE_User" ( "Id" varchar(50) COLLATE "pg_catalog"."default" NOT NULL, "CreateTime" timestamp(6) NOT NULL ) ; COMMENT ON COLUMN "public"."BASE_User"."Id" IS 'GUId主键'; COMMENT ON COLUMN "public"."BASE_User...