Postgresql语句持续更新
Posted 程序媛一枚~
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- 分区表
- partition by
- case when then end
- if else
- 日期：Date，Timestamp，text，String互转
- 时间获取周，月等
- 自增序列
- 创建表，删除表
- 修改表，默认值，重命名列，修改列类型
- 时间序列
- 聚合等，
SELECT '"bar": "baz", "balance": 7.77, "active": false'::json;
-- 创建数据库
createdb mydb;
-- 删除数据库
dropdb mydb;
SELECT version(),current_date;
-- 创建表
CREATE TABLE weather (
city varchar(80),
temp_lo int, -- 最低温度
temp_hi int, -- 最高温度
prcp real, -- 湿度
date date
);
CREATE TABLE cities (
name varchar(80),
location point
);
-- 删除表
DROP TABLE weather;
--插入表数据
INSERT INTO weather VALUES ('San Francisco', 46, 50, 0.25, '1994-11-27');
INSERT INTO cities VALUES ('San Francisco', '(-194.0, 53.0)');
INSERT INTO weather (city, temp_lo, temp_hi, prcp, date)
VALUES ('San Francisco', 43, 57, 0.0, '1994-11-29');
INSERT INTO weather (date, city, temp_hi, temp_lo)
VALUES ('1994-11-29', 'Hayward', 54, 37);
--杀手锏COPY命令
SELECT * FROM ops.t_application_properties
-- POSTGRESQL 9.0前支持，不支持
-- COPY (SELECT * FROM ops.t_application_properties WHERE key LIKE 'service') TO 'C:\\\\Users\\\\Administrator\\\\Desktop\\\\t_application_services.copy';
SELECT DISTINCT city FROM weather order by city;
SELECT * FROM weather;
SELECT * FROM weather, cities WHERE city = name;
-- 按城市找出最低温度中的最高温度
SELECT city FROM weather WHERE temp_lo = (SELECT max(temp_lo) FROM weather);
SELECT city, max(temp_lo) FROM weather GROUP BY city;
SELECT city, max(temp_lo) FROM weather GROUP BY city HAVING max(temp_lo) < 40;
-- 只关心以S开头的城市，最低温度的最高温度
SELECT city, max(temp_lo) FROM weather city LIKE 'S%' GROUP BY city HAVING max(temp_lo) < 40;
UPDATE weather SET temp_hi = temp_hi - 2, temp_lo = temp_lo - 2 WHERE date > '1994-11-28';
DELETE FROM weather WHERE city = 'Hayward';
--视图
CREATE VIEW myview AS
SELECT city, temp_lo, temp_hi, prcp, date, location
FROM weather, cities
WHERE city = name;
SELECT * FROM myview;
--外键辅助进行一些数据引用完整性，cities表必须现有city，才能插入到weather表中
CREATE TABLE cities (
city varchar(80) primary key,
location point
);
CREATE TABLE weather (
city varchar(80) references cities(city),
temp_lo int,
temp_hi int,
prcp real,
date date
);
-- 事务 ACID 在PostgreSQL中，开启一个事务需要将SQL命令用BEGIN和COMMIT命令包围起来。银行事务看起来会是这样：
-- PostgreSQL实际上将每一个SQL语句都作为一个事务来执行。如果我们没有发出BEGIN命令，则每个独立的语句都会被加上一个隐式的BEGIN以及（如果成功）COMMIT来包围它。一组被BEGIN和COMMIT包围的语句也被称为一个事务块。
-- ROLLBACK TO是唯一的途径来重新控制一个由于错误被系统置为中断状态的事务块，而不是完全回滚它并重新启动。
BEGIN;
UPDATE accounts SET balance = balance - 100.00
WHERE name = 'Alice';
SAVEPOINT my_savepoint;
UPDATE accounts SET balance = balance + 100.00
WHERE name = 'Bob';
-- oops ... forget that and use Wally's account
ROLLBACK TO my_savepoint;
UPDATE accounts SET balance = balance + 100.00
WHERE name = 'Wally';
COMMIT;
-- 展示如何将每一个员工的薪水与他/她所在部门的平均薪水进行比较：
SELECT depname, empno, salary, avg(salary) OVER (PARTITION BY depname) FROM empsalary;
-- 部门内员工薪水倒序排列
SELECT depname, empno, salary, rank() OVER (PARTITION BY depname ORDER BY salary DESC) FROM empsalary;
-- 为了在一个字符串中包括一个单引号，可以写两个相连的单引号，例如'Dianne''s horse'。
select 'Dianne''s horse',E'Dianne\\'s horse',$$Dianne's horse$$
-- 一个转义字符串常量可以通过在开单引号前面写一个字母E（大写或小写形式）来指定
select E'\\b' as 退格,E'\\f' as 换页,E'\\n' 换行,E'\\r' 回车,E'\\t' 制表符,E'\\o, \\oo, \\ooo (o = 0–7)' 八进制字节值
select 2^3,sqrt(2);
-- 聚合函数 根据某个字段排序后在聚合
SELECT array_agg(city ORDER BY prcp DESC) FROM weather;
SELECT string_agg(city, ',' ORDER BY city) FROM weather;
-- 直接聚合，并且以''字符串连接
select string_agg('''' || "city" || '''',',') from weather;
SELECT
count(*) AS unfiltered,
count(*) FILTER (WHERE i < 5) AS filtered
FROM generate_series(1,10) AS s(i);
-- generate_series生成序列
SELECT * FROM generate_series(1,10);
-- CROSS JOIN,INNER JOIN,LEFT JOIN,RIGHT JOIN,FULL OUTER JOIN的区别
CREATE TABLE foo (fooid int, foosubid int, fooname text);
CREATE FUNCTION getfoo(int) RETURNS SETOF foo AS $$
SELECT * FROM foo WHERE fooid = $1;
$$ LANGUAGE SQL;
SELECT * FROM getfoo(1) AS t1;
SELECT * FROM foo
WHERE foosubid IN (
SELECT foosubid
FROM getfoo(foo.fooid) z
WHERE z.fooid = foo.fooid
);
CREATE VIEW vw_getfoo AS SELECT * FROM getfoo(1);
SELECT * FROM vw_getfoo;
-- json_to_recordset & generate_series
SELECT *
FROM ROWS FROM
(
json_to_recordset('["a":40,"b":"foo","a":"100","b":"bar"]')
AS (a INTEGER, b TEXT),
generate_series(1, 3)
) AS x (p, q, s)
ORDER BY p;
-- 计算每种商品的销售额
SELECT product_id, p.name, (sum(s.units) * p.price) AS sales
FROM products p LEFT JOIN sales s USING (product_id)
GROUP BY product_id, p.name, p.price;
-- 计算近4周的产品id，名称及利润
SELECT product_id, p.name, (sum(s.units) * (p.price - p.cost)) AS profit
FROM products p LEFT JOIN sales s USING (product_id)
WHERE s.date > CURRENT_DATE - INTERVAL '4 weeks'
GROUP BY product_id, p.name, p.price, p.cost
HAVING sum(p.price * s.units) > 5000;
-- 聚合分组
SELECT brand, size, sum(sales) FROM items_sold GROUP BY GROUPING SETS ((brand), (size), ());
SELECT oid FROM pg_proc WHERE proname LIKE 'bytea%'
-- 数组
CREATE TABLE arr(f1 int[], f2 int[]);
INSERT INTO arr VALUES (ARRAY[[1,2],[3,4]], ARRAY[[5,6],[7,8]]);
SELECT ARRAY[f1, f2, '9,10,11,12'::int[]] FROM arr;
SELECT ARRAY[]::integer[],ARRAY[1,2,3+4],ARRAY[1,2,22.7]::integer[],ARRAY[ARRAY[1,2],ARRAY[3,4]],ARRAY(SELECT oid FROM pg_proc WHERE proname LIKE 'bytea%');
SELECT ARRAY(SELECT ARRAY[i, i*2] FROM generate_series(1,5) AS a(i));
--复杂的case when计算
SELECT CASE WHEN min(employees) > 0
THEN avg(expenses / employees)
END
CASE COALESCE(sum(employees),0)
WHEN 0 THEN 0.0
ELSE SUM(salary)/sum(employees)
END
-- 计算比率
(CASE COALESCE(sum(employees),0)
WHEN 0 THEN '0.00%'
ELSE concat(round(SUM(salary)*100.0/sum(employees)),2),'%')
END) excelRate
(CASE WHEN time > 1440 THEN time/1440||'天'||time%1440/60||'小时'||time%60||'分钟'
WHEN time > 60 THEN time/60||'小时'||time%60||'分钟'
ELSE time%60||'分钟'
END) weekAvg
FROM departments;
-- 创建表
drop table if exists my_first_table;
CREATE TABLE if not exists my_first_table (
first_column text,
second_column integer
);
-- 自增序列 主键 唯一 非空约束 外键
CREATE TABLE products (
product_no integer DEFAULT nextval('products_product_no_seq') PRIMARY KEY,
name text NOT NULL,
price numeric DEFAULT 9.99,
number CHECK (number > 0),
discounted_price numeric CONSTRAINT positive_price CHECK (discounted_price > 0),
CONSTRAINT valid_discount CHECK (price > discounted_price), --打折价格低于正常价格
UNIQUE (product_no)
);
-- 组合约束
CREATE TABLE example (
a integer,
b integer,
c integer,
UNIQUE (a, c)
);
CREATE TABLE products (
product_no integer PRIMARY KEY,
name text,
price numeric
);
CREATE TABLE orders (
order_id integer PRIMARY KEY,
shipping_address text
);
CREATE TABLE order_items (
product_no integer REFERENCES products ON DELETE RESTRICT, --不允许删除被引用的行
order_id integer REFERENCES orders ON DELETE CASCADE,--删除时级联删除 还有其他两种选项：SET NULL和SET DEFAULT。这些将导致在被引用行被删除后，引用行中的引用列被置为空值或它们的默认值。
quantity integer,
PRIMARY KEY (product_no, order_id)
);
-- 序列发生器取值
CREATE TABLE tablename (
colname SERIAL
);
-- 等价于以下语句：
CREATE SEQUENCE tablename_colname_seq AS integer;
CREATE TABLE tablename (
colname integer NOT NULL DEFAULT nextval('tablename_colname_seq')
);
ALTER SEQUENCE tablename_colname_seq OWNED BY tablename.colname;
--创建序列
CREATE SEQUENCE serial START 101;
-- 从这个序列中选取下一个数字：
SELECT nextval('serial');
SELECT x,
round(x::numeric) AS num_round,
round(x::double precision) AS dbl_round
FROM generate_series(-3.5, 3.5, 1) as x;
-- 生成时间序列
select * from generate_series(to_timestamp(1658937600)::DATE,to_timestamp(1659537600)::DATE,'1 day')
-- 生成char时间序列
select to_char(generate_series(to_timestamp(1658937600)::DATE,to_timestamp(1659537600)::DATE,'1 day'),'yyyy-mm-dd')
-- 创建一个范围分区表：
CREATE TABLE measurement (
logdate date not null,
peaktemp int,
unitsales int
) PARTITION BY RANGE (logdate);
-- 创建在分区键中具有多个列的范围分区表：
CREATE TABLE measurement_year_month (
logdate date not null,
peaktemp int,
unitsales int
) PARTITION BY RANGE (EXTRACT(YEAR FROM logdate), EXTRACT(MONTH FROM logdate));
-- 创建列表分区表：
CREATE TABLE cities (
city_id bigserial not null,
name text not null,
population bigint
) PARTITION BY LIST (left(lower(name), 1));
-- 建立哈希分区表:
CREATE TABLE orders (
order_id bigint not null,
cust_id bigint not null,
status text
) PARTITION BY HASH (order_id);
-- 创建范围分区表的分区：
CREATE TABLE measurement_y2016m07
PARTITION OF measurement (
unitsales DEFAULT 0
) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');
--使用分区键中的多个列，创建范围分区表的几个分区：
CREATE TABLE measurement_ym_older
PARTITION OF measurement_year_month
FOR VALUES FROM (MINVALUE, MINVALUE) TO (2016, 11);
CREATE TABLE measurement_ym_y2016m11
PARTITION OF measurement_year_month
FOR VALUES FROM (2016, 11) TO (2016, 12);
CREATE TABLE measurement_ym_y2016m12
PARTITION OF measurement_year_month
FOR VALUES FROM (2016, 12) TO (2017, 01);
CREATE TABLE measurement_ym_y2017m01
PARTITION OF measurement_year_month
FOR VALUES FROM (2017, 01) TO (2017, 02);
-- 创建列表分区表的分区：
CREATE TABLE cities_ab
PARTITION OF cities (
CONSTRAINT city_id_nonzero CHECK (city_id != 0)
) FOR VALUES IN ('a', 'b');
-- 创建本身是分区的列表分区表的分区，然后向其添加分区：
CREATE TABLE cities_ab
PARTITION OF cities (
CONSTRAINT city_id_nonzero CHECK (city_id != 0)
) FOR VALUES IN ('a', 'b') PARTITION BY RANGE (population);
CREATE TABLE cities_ab_10000_to_100000
PARTITION OF cities_ab FOR VALUES FROM (10000) TO (100000);
-- 建立哈希分区表的分区：
CREATE TABLE orders_p1 PARTITION OF orders
FOR VALUES WITH (MODULUS 4, REMAINDER 0);
CREATE TABLE orders_p2 PARTITION OF orders
FOR VALUES WITH (MODULUS 4, REMAINDER 1);
CREATE TABLE orders_p3 PARTITION OF orders
FOR VALUES WITH (MODULUS 4, REMAINDER 2);
CREATE TABLE orders_p4 PARTITION OF orders
FOR VALUES WITH (MODULUS 4, REMAINDER 3);
-- 建立默认分区：
CREATE TABLE cities_partdef
PARTITION OF cities DEFAULT;
-- 移除旧数据最简单的选择是删除掉不再需要的分区：可以非常快地删除数百万行记录，因为它不需要逐个删除每个记录。不过注意需要在父表上拿到ACCESS EXCLUSIVE锁。
DROP TABLE measurement_y2006m02;
-- 另一种通常更好的选项是把分区从分区表中移除，但是保留它作为一个独立的表：
ALTER TABLE measurement DETACH PARTITION measurement_y2006m02;
-- 父表创建索引子表自动也有索引，或者父表创建索引子表不拥有；
CREATE INDEX measurement_usls_idx ON measurement (unitsales); --子表将自动拥有索引
CREATE INDEX measurement_usls_idx ON ONLY measurement (unitsales); --子表将不拥有索引
--父表也将能使用子表的索引
CREATE INDEX measurement_usls_idx ON ONLY measurement (unitsales);
CREATE INDEX measurement_usls_200602_idx
ON measurement_y2006m02 (unitsales);
ALTER INDEX measurement_usls_idx
ATTACH PARTITION measurement_usls_200602_idx;
-- 创建一个范围分区表：
CREATE TABLE measurement (
logdate date not null,
peaktemp int,
unitsales int
) PARTITION BY RANGE (logdate);
-- 创建在分区键中具有多个列的范围分区表：
CREATE TABLE measurement_year_month (
logdate date not null,
peaktemp int,
unitsales int
) PARTITION BY RANGE (EXTRACT(YEAR FROM logdate), EXTRACT(MONTH FROM logdate));
-- 创建列表分区表：
CREATE TABLE cities (
city_id bigserial not null,
name text not null,
population bigint
) PARTITION BY LIST (left(lower(name), 1));
-- 建立哈希分区表:
CREATE TABLE orders (
order_id bigint not null,
cust_id bigint not null,
status text
) PARTITION BY HASH (order_id);
-- 创建范围分区表的分区：
CREATE TABLE measurement_y2016m07
PARTITION OF measurement (
unitsales DEFAULT 0
) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');
-- 使用分区键中的多个列-- 创建范围分区表的几个分区：
CREATE TABLE measurement_ym_older
PARTITION OF measurement_year_month
FOR VALUES FROM (MINVALUE, MINVALUE) TO (2016, 11);
CREATE TABLE measurement_ym_y2016m11
PARTITION OF measurement_year_month
FOR VALUES FROM (2016, 11) TO (2016, 12);
CREATE TABLE measurement_ym_y2016m12
PARTITION OF measurement_year_month
FOR VALUES FROM (2016, 12) TO (2017, 01);
CREATE TABLE measurement_ym_y2017m01
PARTITION OF measurement_year_month
FOR VALUES FROM (2017, 01) TO (2017, 02);
-- 创建列表分区表的分区：
CREATE TABLE cities_ab
PARTITION OF cities (
CONSTRAINT city_id_nonzero CHECK (city_id != 0)
) FOR VALUES IN ('a', 'b');
-- 创建本身是分区的列表分区表的分区，然后向其添加分区：
CREATE TABLE cities_ab
PARTITION OF cities (
CONSTRAINT city_id_nonzero CHECK (city_id != 0)
) FOR VALUES IN ('a', 'b') PARTITION BY RANGE (population);
CREATE TABLE cities_ab_10000_to_100000
PARTITION OF cities_ab FOR VALUES FROM (10000) TO (100000);
-- 建立哈希分区表的分区：
CREATE TABLE orders_p1 PARTITION OF orders
FOR VALUES WITH (MODULUS 4, REMAINDER 0);
CREATE TABLE orders_p2 PARTITION OF orders
FOR VALUES WITH (MODULUS 4, REMAINDER 1);
CREATE TABLE orders_p3 PARTITION OF orders
FOR VALUES WITH (MODULUS 4, REMAINDER 2);
CREATE TABLE orders_p4 PARTITION OF orders
FOR VALUES WITH (MODULUS 4, REMAINDER 3);
-- 建立默认分区：
CREATE TABLE cities_partdef
PARTITION OF cities DEFAULT;
-- 增加列
ALTER TABLE products ADD COLUMN description text;
ALTER TABLE products ADD COLUMN description text CHECK (description <> '');
-- 移除列
ALTER TABLE products DROP COLUMN description;
ALTER TABLE products DROP COLUMN description CASCADE;
-- 增加约束
ALTER TABLE products ADD CHECK (name <> '');
ALTER TABLE products ADD CONSTRAINT some_name UNIQUE (product_no);
ALTER TABLE products ADD FOREIGN KEY (product_group_id) REFERENCES product_groups;
ALTER TABLE products ALTER COLUMN product_no SET NOT NULL;
-- 移除约束
ALTER TABLE products DROP CONSTRAINT some_name;
ALTER TABLE products ALTER COLUMN product_no DROP NOT NULL;
-- 更改列默认值，移除默认值
ALTER TABLE products ALTER COLUMN price SET DEFAULT 7.77;
ALTER TABLE products ALTER COLUMN price DROP DEFAULT;
-- 修改列类型
ALTER TABLE products ALTER COLUMN price TYPE numeric(10,2);
-- 重命名列
ALTER TABLE products RENAME COLUMN product_no TO product_number;
-- 重命名表
ALTER TABLE products RENAME TO items;
-- 创建模式
CREATE SCHEMA hollywood;
CREATE TABLE hollywood.films (title text, release date, awards text[]);
CREATE VIEW hollywood.winners AS
SELECT title, release FROM hollywood.films WHERE awards IS NOT NULL;
-- 删除模式
DROP SCHEMA hollywood CASCADE;
-- 定义外部统计
CREATE TABLE t1 (
a int,
b int
);
INSERT INTO t1 SELECT i/100, i/500
FROM generate_series(1,1000000) s(i);
ANALYZE t1;
-- 匹配行的数量将被大大低估：
EXPLAIN ANALYZE SELECT * FROM t1 WHERE (a = 1) AND (b = 0);
CREATE STATISTICS s1 (dependencies) ON a, b FROM t1;
ANALYZE t1;
-- 现在行计数估计会更准确：
EXPLAIN ANALYZE SELECT * FROM t1 WHERE (a = 1) AND (b = 0);
CREATE TABLE t2 (
a int,
b int
);
INSERT INTO t2 SELECT mod(i,100), mod(i,100)
FROM generate_series(1,1000000) s(i);
CREATE STATISTICS s2 (mcv) ON a, b FROM t2;
ANALYZE t2;
-- valid combination (found in MCV)
EXPLAIN ANALYZE SELECT * FROM t2 WHERE (a = 1) AND (b = 1);
-- invalid combination (not found in MCV)
EXPLAIN ANALYZE SELECT * FROM t2 WHERE (a = 1) AND (b = 2);
-- CREATE TABLE AS创建一个表，并且用由一个SELECT命令计算出来的数据填充 该表。该表的列具有和SELECT的输出列 相关的名称和数据类型（不过可以通过给出一个显式的新列名列表来覆盖这些列名）。
-- CREATE TABLE AS和创建一个视图有些相似，但是实际上非常不同：它会创建一个新表并且只计算该查询一次用来初始填充新表。这个新表将不会跟踪该查询源表的后续变化。相反， 一个视图只要被查询，它的定义SELECT 语句就会被重新计算。
CREATE TABLE films_recent AS SELECT * FROM films WHERE date_prod >= '2002-01-01';
- 要完全地复制一个表，也可以使用TABLE命令的 简短形式：
CREATE TABLE films2 AS TABLE films;
-- 触发器
-- 历史数据更新
update test_geo set lon=st_x(st_geomfromtext(lastp,4326)),lat = st_y(st_geomfromtext(lastp,4326));
-- 触发器更新
create or replace FUNCTION func_updatelastp() RETURNS trigger
AS
$func_updatelastp$
BEGIN
update test_geo set lon=st_x(st_geomfromtext(lastp,4326)),lat = st_y(st_geomfromtext(lastp,4326)) where id = NEW.id;
RETURN NEW;
END;
$func_updatelastp$ LANGUAGE plpgsql;
CREATE TRIGGER updatelastp_trigger AFTER INSERT OR UPDATE OF lastp ON test_geo
FOR EACH ROW EXECUTE PROCEDURE func_updatelastp();
-- eg: 创建触发器
CREATE FUNCTION trigf() RETURNS trigger
AS 'filename'
LANGUAGE C;
CREATE TRIGGER tbefore BEFORE INSERT OR UPDATE OR DELETE ON ttest
FOR EACH ROW EXECUTE FUNCTION trigf();
CREATE TRIGGER tafter AFTER INSERT OR UPDATE OR DELETE ON ttest
FOR EACH ROW EXECUTE FUNCTION trigf();
drop table if exists test_geo;
CREATE TABLE if not exists test_geo
(
id bigint NOT NULL,
line_geom geometry,
lastp text,
lat numeric,
lon numeric
);
INSERT INTO test_geo(id, line_geom, lastp)
VALUES(1,ST_GeomFromText('LINESTRING(118.810687877626 31.9125455099001,118.809488683078 31.9106356486321)',4326),'POINT(115.6 30.9)');
INSERT INTO test_geo(id, line_geom,lastp)
VALUES(2,ST_GeomFromText('LINESTRING(118.8094259903 31.9126940986126,118.809430971813 31.9125951121883)',4326),'POINT(113.6 34.9)');
INSERT INTO test_geo(id, line_geom,lastp)
VALUES(3,ST_GeomFromText('POLYGON((113.412350 29.971457,115.156783 29.971457,115.156783 31.428195,113.412350 31.428195,113.412350 29.971457))',4326),'POINT(116.6 40.9)');
INSERT INTO test_geo(id, line_geom)
VALUES(4,ST_GeomFromText('POINT(115.6 30.9)',4326));
INSERT INTO test_geo(id, line_geom,lastp)
VALUES(6,ST_GeomFromText('POLYGON((113.412350 29.971457,115.156783 29.971457,115.156783 31.428195,113.412350 31.428195,113.412350 29.971457))',4326),'POINT(120.1 35.2)');
INSERT INTO test_geo(id, line_geom,lastp)
VALUES(7,ST_GeomFromText('POLYGON((113.412350 29.971457,115.156783 29.971457,115.156783 31.428195,113.412350 31.428195,113.412350 29.971457))',4326),'POINT(118.1 38.2)');
select *,ST_AsText(line_geom),ST_LengthSpheroid(line_geom,'SPHEROID["WGS 84",6378137,298.257223563]') from test_geo;
select st_geomfromtext(lastp,4326),st_x(st_geomfromtext(lastp,4326)),st_y(st_geomfromtext(lastp,4326)),* from test_geo;
--构建表并进行geomtry与wkt互转，计算长度等；
CREATE TABLE if not exists test_geo
(
id bigint NOT NULL,
line_geom geometry
);
INSERT INTO test_geo(id, line_geom)
VALUES(1,ST_GeomFromText('LINESTRING(118.810687877626 31.9125455099001,118.809488683078 31.9106356486321)',4326));
INSERT INTO test_geo(id, line_geom)
VALUES(1,ST_GeomFromText('POLYGON((113.412350 29.971457,115.156783 29.971457,115.156783 31.428195,113.412350 31.428195,113.412350 29.971457))',4326));
INSERT INTO test_geo(id, line_geom)
VALUES(1,ST_GeomFromText('POINT(115.6 30.9)',4326));
select *,ST_AsText(line_geom),ST_LengthSpheroid(line_geom,'SPHEROID["WGS 84",6378137,298.257223563]') from test_geo;
-- 直接构建点、线计算距离
select
ST_Distance(
ST_SetSRID(ST_MakePoint(118.810687877626,31.9125455099001),4326)::geography,
ST_SetSRID(ST_MakePoint(118.809488683078,31.9106356486321),4326)::geography
),
ST_LengthSpheroid(ST_GeomFromText('LINESTRING(118.810687877626 31.9125455099001,118.809488683078 31.9106356486321)',4326),
'SPHEROID["WGS 84",6378137,298.257223563]'),
ST_Length(
ST_MakeLine(
ST_MakePoint(118.810687877626,31.9125455099001),
ST_MakePoint(118.809488683078,31.9106356486321)
)::geography
)
select ST_GeomFromText('LINESTRING (115.805946 39.2572185, 115.8059521 39.2572183, 115.8059566 39.2572192, 115.805962 39.2572191, 115.8059678 39.2572183, 115.8059764 39.2572184, 115.8059806 39.2572192, 115.8059855 39.2572193, 115.8059884 39.2572182, 115.8059937 39.2572182, 115.8060005 39.2572196, 115.8060042 39.2572216, 115.8060075 39.2572206, 115.8060137 39.2572209)',4326),ST_GeomFromText('LINESTRING ( 115.80597777855581 39.257218662582055, 115.805976 39.257228 )',4326)
INSERT INTO test_geo(id, line_geom) VALUES(10,ST_GeomFromText('LINESTRING (115.805946 39.2572185, 115.8059521 39.2572183, 115.8059566 39.2572192, 115.805962 39.2572191, 115.8059678 39.2572183, 115.8059764 39.2572184, 115.8059806 39.2572192, 115.8059855 39.2572193, 115.8059884 39.2572182, 115.8059937 39.2572182, 115.8060005 39.2572196, 115.8060042 39.2572216, 115.8060075 39.2572206, 115.8060137 39.2572209)',4326));
INSERT INTO test_geo(id, line_geom) VALUES(11,ST_GeomFromText('LINESTRING ( 115.80597777855581 39.257218662582055, 115.805976 39.257228 )',4326));
select * from test_geo where id >9;
-- 日期转换
select 1659351600000,1659355199999,
cast('1659351600000' as bigint) as char2bigint,
cast('1659351600000' as bigint)/1000 as s,
to_timestamp(1659355199)::DATE as date,
to_date('2022-08-01 19:59:59.000000', 'yyyy-mm-dd hh24:mi:ss.us' ) as date2,
to_char(to_timestamp(cast('1659351600000' as bigint)/1000),'YYYY-MM-DD HH24:MI:SS') as char2ts24,
to_char(to_timestamp(1659351600000),'yyyy-mm-dd hh:mm:ss') as msts,
to_char(to_timestamp(1659355199999),'yyyy-mm-dd hh:mm:ss') as mste,
to_char(to_timestamp(1659351600),'yyyy-mm-dd hh:mm:ss') as sts,
to_char(to_timestamp(1659355199),'yyyy-mm-dd hh:mm:ss') as stE,
to_char(to_timestamp(1659351600),'YYYY-MM-DD HH24:MI:SS') as ts24,
to_char(to_timestamp(1659355199),'YYYY-MM-DD HH24:MI:SS') as te24,
to_char(to_timestamp(1659355199),'yyyy-mm-dd hh24:mi:ss.us') as te24_2
-- 生成00:00~23:00
select '0' || generate_series(0,9)||':00' as hour union all select generate_series(10,23)||':00'
-- 生成时间戳s序列
select t.hour,to_timestamp(t.hour),to_char(to_timestamp(t.hour),'yyyy-mm-dd hh24:mi:ss.us'),to_char(to_timestamp(t.hour),'yyyy-mm-dd hh24:00')
from (select generate_series(1659196800,1660015435,86400) as hour) t
-- 日期序列
select generate_series('2022-07-09'::date,'2022-08-08'::date,'1 day')::date
-- date转text
select d.date,d.date::TEXT from (select generate_series('2022-07-09'::date,'2022-08-08'::date,'1 day')::date as date) d
-- 生成当天小时整点的时间戳，字符串转日期date年月日时分秒，字符串转day年月日，字符串转timestamp，字符串转ms，m
select '2022-08-10 '||hour|| ':00' as dayYMDHMS,('2022-08-10 '||hour|| ':00')::date as date1,
to_date('2022-08-10 '||hour|| ':00', 'yyyy-mm-dd hh24:mi:ss.us' ) as date2,
to_timestamp('2022-08-10 '||hour|| ':00', 'yyyy-mm-dd hh24:mi:ss.us') timestamp1,
floor(extract(epoch from to_timestamp('2022-08-10 '||hour|| ':00', 'yyyy-mm-dd hh24:mi:ss.us'))*1000) ms,
floor(extract(epoch from to_timestamp('2022-08-10 '||hour|| ':00', 'yyyy-mm-dd hh24:mi:ss.us'))) s,
floor(extract(epoch from to_timestamp('2022-08-10 '||hour|| ':00', 'yyyy-mm-dd hh24:mi:ss.us'))*1000)+3600*1000 msE
from (select '0' || generate_series(0,9)||':00' as hour union all select generate_series(10,23)||':00' as hour) t
-- 字符串截取和替换: position截取lat,lon
select p.position,SUBSTR(SPLIT_PART(position,' ',1),7) as lon,REPLACE(SPLIT_PART(position,' ',2),')','') as lat from (select 'Point(114.23451279684568 34.892324932024)' as position) as p
-- coalesce：返回其参数中第一个非空表达式
select COALESCE(3,1),COALESCE('其他','1')
-- case when可以一行统计多个状态的值，totalLength,finishLength,total,failCnt,successCnt
select ds,sum(track_length) as total_track_length,sum(case when status=5 then track_length else 0 end) as finish_track_length,
count(1) as total,sum(case when status=5 then 1 else 0 end) as finish_cnt,sum(case when status=4 then 1 when status=7 then 1 else 0 end) as fail_cnt,
sum(case when status=6 then 1 else 0 end) as executing_cnt from t_task group by ds order by ds
- 时间戳转日期
select 1660197595000,to_timestamp(1660198903355/1000)
drop table if exists weather2;
CREATE TABLE weather2 (
city varchar(80),
temp_lo int, -- 最低温度
temp_hi int, -- 最高温度
prcp real, -- 湿度
date date
);
ALTER TABLE weather2 ADD CONSTRAINT date_uniq UNIQUE (date, city);
SELECT *
FROM ROWS FROM
(
json_to_recordset('["a":40,"b":"foo","a":"100","b":"bar"]')
AS (a INTEGER, b TEXT),
generate_series(1, 3)
) AS x (p, q, s)
ORDER BY p;
-- on conflict 不更新，更新
insert into weather2 as tos (city,temp_lo,date) SELECT p,q,s::date
FROM ROWS FROM
(
json_to_recordset('["a":40,"b":"sh","a":"100","b":"qd","a":"10","b":"qdd","a":"3","b":"bj"]')
AS (b TEXT,a INTEGER),
generate_series(1, 4),
generate_series('2022-08-06'::date,'2022-08-09'::date,'1 day')
) AS x (p,q,r,s)
-- ORDER BY p
-- on conflict(date, city) do update set temp_lo = excluded.temp_lo; --保留当前值
-- on conflict(date, city) do update set temp_lo = tos.temp_lo; --保留原始值
-- on conflict(date, city) do nothing; --保留原始值
on conflict on constraint date_uniq do nothing; --保留原始值
on conflict(date, city) do update set temp_lo = tos.temp_lo+excluded.temp_lo -- 原始值与当前值相加
select * from weather2
-- 找出占用磁盘最大的表和索引
-- SELECT relname, relpages FROM pg_class ORDER BY relpages DESC;
-- 某张表的磁盘占用量
SELECT pg_relation_filepath(oid), relpages FROM pg_class WHERE relname = 't_application';
--
SELECT relname, relpag以上是关于Postgresql语句持续更新的主要内容，如果未能解决你的问题，请参考以下文章