1.设置数据库主键自增
1.1 建表时
在创建数据库时,将要自增的字段设置为 serial类型.
1.2 当数据已经修建完成后的补救方案.
CREATE SEQUENCE 表名_字段名_seq
    START WITH 1
    INCREMENT BY 1
    NO MINVALUE
    NO MAXVALUE
    CACHE 1;
ALTER TABLE 表名 ALTER COLUMN 字段名
SET DEFAULT nextval( '表名_字段名_seq' );

2. 设置分页查询 使用limit
SELECT * FROM 表名
LIMIT 每页显示数量 OFFSET 起始位置

3.Bool类型
SELECT * FROM vip WHERE is_valid = true

4.查询字符串时,要使用 ‘’ 包起来,不能使用"".

在pg中的sql，单引号用来标识实际的值，双引号用来标识表名（table name）或列名（column name）等数据库中存在的值。

1.以下两种操作均不会删除表中数据

#删除带上回滚一起执行

delete from classinfo where classid=1;

ROLLBACK;

#退出当前事务

delete from classinfo where classid=1;

ABORT TRANSACTION;

 

 

2.定义枚举类型，current_mood为枚举类型，值只能输入'sad', 'ok', 'happy'其中一个，输入其它报错

CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy');

CREATE TABLE person (

    name text,

    current_mood mood

);

 

 

3.非常好用的PARTITION BY

想要分组后再进行条件筛选，每组选出符合条件的数据，group by 使用时select后面的字段必须出现在 GROUP BY 子句中或者在聚合函数中使用，所以使用起来非常不方便

SELECT

    iiii,

    rain_1hour,

    data_time,

    ROW_NUMBER () OVER (PARTITION BY iiii ORDER BY xxx desc)as rownumber

FROM

    w_data_site_rain

WHERE

    data_time < '20180522091500'

  and rownumber<=1

 

获取到了分组中最大的一组值

 

 

4.循环删除不需要数据插入到新的表中

WITH moved_rows AS (

   DELETE FROM w_data_site_rain

   WHERE

      data_time < '20180522091500'

   RETURNING * 

)

INSERT INTO w_data_site_rain (SELECT * FROM moved_rows)

 

 

 

 

1.安装后授权给所有IP和用户链接

  1). 修改pgsql/data/postgresql.conf 配置文件

   listen_addresses = '*'

  2).修改pgsql/data/ph_hba.conf 配置文件

   host all all 0.0.0.0/0 md5

ThinkPHP version: 5.1.*
使用 ThinkPHP 框架连接PGSQL时遇到的坑, 记录下来...避免一次一顿百度....
改配置
修改 /config/database.php 这个配置文件
connect pgsql config
如果此时对数据操作会报错
could not find driver
开扩展
修改 php.ini 打开连接pgsql需要的扩展, 如果没有请到 http://pecl.php.net/ 下载对应版本的扩展
修改了 php.ini 别忘了重启apache/nginx
php extensions
执行sql
在使用之前请先在 navicat 中运行一下SQL, ThinkPHP中自带这一个SQL文件
/thinkphp/library/think/db/connector/pgsql.sql
CREATE OR REPLACE FUNCTION pgsql_type(a_type varchar) RETURNS varchar AS
$BODY$
DECLARE
v_type varchar;
BEGIN
IF a_type='int8' THEN
v_type:='bigint';
ELSIF a_type='int4' THEN
v_type:='integer';
ELSIF a_type='int2' THEN
v_type:='smallint';
ELSIF a_type='bpchar' THEN
v_type:='char';
ELSE
v_type:=a_type;
END IF;
RETURN v_type;
END;
$BODY$
LANGUAGE PLPGSQL;
CREATE TYPE "public"."tablestruct" AS (
"fields_key_name" varchar(100),
"fields_name" VARCHAR(200),
"fields_type" VARCHAR(20),
"fields_length" BIGINT,
"fields_not_null" VARCHAR(10),
"fields_default" VARCHAR(500),
"fields_comment" VARCHAR(1000)
);
CREATE OR REPLACE FUNCTION "public"."table_msg" (a_schema_name varchar, a_table_name varchar) RETURNS SETOF "public"."tablestruct" AS
$body$
DECLARE
v_ret tablestruct;
v_oid oid;
v_sql varchar;
v_rec RECORD;
v_key varchar;
BEGIN
SELECT
pg_class.oid  INTO v_oid
FROM
pg_class
INNER JOIN pg_namespace ON (pg_class.relnamespace = pg_namespace.oid AND lower(pg_namespace.nspname) = a_schema_name)
WHERE
pg_class.relname=a_table_name;
IF NOT FOUND THEN
RETURN;
END IF;
v_sql='
SELECT
pg_attribute.attname AS fields_name,
pg_attribute.attnum AS fields_index,
pgsql_type(pg_type.typname::varchar) AS fields_type,
pg_attribute.atttypmod-4 as fields_length,
CASE WHEN pg_attribute.attnotnull  THEN ''not null''
ELSE ''''
END AS fields_not_null,
pg_attrdef.adsrc AS fields_default,
pg_description.description AS fields_comment
FROM
pg_attribute
INNER JOIN pg_class  ON pg_attribute.attrelid = pg_class.oid
INNER JOIN pg_type   ON pg_attribute.atttypid = pg_type.oid
LEFT OUTER JOIN pg_attrdef ON pg_attrdef.adrelid = pg_class.oid AND pg_attrdef.adnum = pg_attribute.attnum
LEFT OUTER JOIN pg_description ON pg_description.objoid = pg_class.oid AND pg_description.objsubid = pg_attribute.attnum
WHERE
pg_attribute.attnum > 0
AND attisdropped <> ''t''
AND pg_class.oid = ' || v_oid || '
ORDER BY pg_attribute.attnum' ;
FOR v_rec IN EXECUTE v_sql LOOP
v_ret.fields_name=v_rec.fields_name;
v_ret.fields_type=v_rec.fields_type;
IF v_rec.fields_length > 0 THEN
v_ret.fields_length:=v_rec.fields_length;
ELSE
v_ret.fields_length:=NULL;
END IF;
v_ret.fields_not_null=v_rec.fields_not_null;
v_ret.fields_default=v_rec.fields_default;
v_ret.fields_comment=v_rec.fields_comment;
SELECT constraint_name INTO v_key FROM information_schema.key_column_usage WHERE table_schema=a_schema_name AND table_name=a_table_name AND column_name=v_rec.fields_name;
IF FOUND THEN
v_ret.fields_key_name=v_key;
ELSE
v_ret.fields_key_name='';
END IF;
RETURN NEXT v_ret;
END LOOP;
RETURN ;
END;
$body$
LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;
COMMENT ON FUNCTION "public"."table_msg"(a_schema_name varchar, a_table_name varchar)
IS '获得表信息';
---重载一个函数
CREATE OR REPLACE FUNCTION "public"."table_msg" (a_table_name varchar) RETURNS SETOF "public"."tablestruct" AS
$body$
DECLARE
v_ret tablestruct;
BEGIN
FOR v_ret IN SELECT * FROM table_msg('public',a_table_name) LOOP
RETURN NEXT v_ret;
END LOOP;
RETURN;
END;
$body$
LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;
COMMENT ON FUNCTION "public"."table_msg"(a_table_name varchar)
IS '获得表信息';