PostgreSQL 是世界上功能最强大的开源关系型数据库，除了标准的 SQL 的支持外，还有丰富的特性，可以通过扩展来增强数据库的能力，如uuid-ossp，pgcrypto，hstore，PostGIS等扩展。支持如 hstore、range、GIS、json 等更多的数据类型。此外，Greenplum也是基于PG来提供结构化大数据分析仓库解决方案。本文整理了postgre常用基本操作，包括：命令行操作、查询语句以及postgis空间操作等相关语句。
1 命令行操作
postgresql备份：
pg_dump -U postgres -d gisportal -F c -f i:\db2.dump
postgresql还原：
pg_restore -U postgres -d gisportal i:\db2.dump pg_restore -U postgres -d gisportal e:\postgres-20150420.backup
备份单张表：
pg_dump -U postgres -F c -b -v -f i:\test.bak -t sqs.test gisportal
备份整个数据库（非模式）：
pg_dump -U postgres -F c -b -v -f i:\test.bak -t sqs.test gisportal
备份数据库下的模式：
pg_dump -U postgres -F c -b -v -f i:\test.bak -n sqs gisportal
还原单张表：
pg_restore -U postgres -W -d gisportal -v "d:\poi.bak"
要执行语句，先执行：cd postgresql安装目录bin中
pg_dump -U postgres -F c -f i:\gisportal.dump gisportal（备份整个数据库，备份单个模式表为另一种写法） pg_dump -h localhost -U postgres(用户名) 数据库名(缺省时同用户名) -t table(表名) >/data/dum.sql pg_dump -h localhost -U postgres gisportal -t 省界_region >i:\pros.sql
2 基本操作
创建表格
create table schema_name."table_name"( id integer, name character varying, geom geometry)
新建表格并复制某表内容
create table table1 as select * from table2
插入另一张表的整列：
insert into sqs.sqs_role(username) select username from sqs.sqs_user
添加多个列
alter table "table_name" add "num_1" INTEGER, add "num_2" INTEGER, add "length" FLOAT ...
更新列
UPDATE table1 set pop1 = a.pop from (select "OID", pop from "table2" where pop != 0) a where table1."OID" = a."OID"
列类型转换
1）表格新建一列 update table1 set num1 = num1::integer 2）直接修改 alter table table_1 alter column num1 type integer
查询表的字段类型
select column_name, data_type from information_schema.columns where table_name = 'gridbuffer_wgs'
设置null为零值
update schema."table_name" set "column_name" = 0 where "column_name" is null;
插入当天日期date：
update sqs.sqs_shopmall set version=current_date;
截取字符：
update sqs.sqs_poi2 set prcode=substring(prcode,1,2) (index从1开始，1保留)
空字符串处理：
update property set memorial_no = btrim(memorial_no, ' ') where memorial_no like ' %' update property set memorial_no = 2 where memorial_no= btrim(memorial_no, ' ')
多条件模糊查询：
SELECT * FROM table WHERE column LIKE 'Text%' OR column LIKE 'Link%' OR column LIKE 'Hello%' OR column LIKE '%World%'
只查询前几条数据：
LIMIT num OFFSET startNum //可以实现指定条数开始取几条
替换replace：
update cz_basedata_test2 set cnty=replace(cnty,city,'')//不可为null，否则整列将会变为null
3 数值统计
类别统计 (case when语句）
select b.id, sum(case when c.category = '公交车站' then 1 end) "公交车站" from schema."table_name" b left join schema.table_2 c on st_intersects(b.geom, c.geom)
and c.cityname = '上海'
group by b.id
4 PostGIS空间操作
查询投影类型
select st_srid(geom) from table
投影类型转换
update table_1 set geom_4326 = st_transform(geom, 4326)
计算路网长度
select b.id, sum(st_length(st_intersection(geography(b.geom),a.geom))) length from schema."table1" b left join schema2.table2 a on st_intersects(a.geom, b.geom) and a.city = '深圳' group by b.id
计算相交面积
ST_Area(ST_INTERSECTION(b.geom_gcj, c.geom))
计算缓冲区
st_buffer(geography(a.geom_gcj), 3000) -- 计算完后需要再进行geometry转换 geometry(st_buffer(geography(a.geom_gcj), 5000))
计算面积（根据geometry计算面积）
update sqs.sqs_town set totarea=st_area(geography(geom))/1000000
计算距离（包含经纬度转换地理坐标）
select name,st_astext(geom) as geomtext, st_distance(Geography(ST_PointFromText('POINT(121.43543 31.2399)',4326)),Geography(geom)) as distance from table_1 where ST_Intersects(st_buffer(geography(ST_PointFromText('POINT(121.43543 31.2399)',4326)),3000),geom) and dlvydate> date '2010-01-01'
交叉计算： select st_astext(geom) as GeomText ,”County” ,jdlon as Centerx , jdlat as Centery ,( people::DECIMAL/area::DECIMAL*1000000.0 )::INT as Density from vtown where ST_Intersects(st_buffer( geography( ST_PointFromText(‘POINT(121.492498 31.229649)’,4326)),4000),geom) 数组转换为geometry(对百度数组也适用)：
select name from sqs.sqs_pipeline where ST_Intersects(ST_GeomFromText('POLYGON((121.550391 31.048365,121.845897 31.063214,121.734364 30.859081,121.580286 30.940391,121.550391 31.048365))',4326),geom) select name from sqs.sqs_pipeline where ST_Within(geom,ST_PolygonFromText('POLYGON((121.550391 31.048365,121.845897 31.063214,121.734364 30.859081,121.580286 30.940391,121.550391 31.048365))',4326)) and status=1
根据geom计算x、y：
update sqs.sqs_poi set lng=st_x(geom),lat=st_y(geom)
获取点geometry的点x、y坐标：
select *, st_x(geom), st_y(geom)
from sqs.sqs_store
where status=1
and username='admin'
and ST_Within(geom,ST_GeomFromText('POLYGON((121.289092 31.38394,121.333648 31.275857,121.462429 31.333862,121.459267 31.38172,121.379928 31.405393,121.289092 31.38394))',4326))
点转换为geometry：
update sqs.sqs_pipeline
set pipelineid='pp00000008', name='admin', geom=ST_PointFromText('POINT(121.845897 31.063214 )',4326),status=1;
update sqs.yichang
set geom=ST_PointFromText('POINT('||lng||' '||lat||')',4326); update sqs.sqs_pipeline_wfztest set geomta500=ST_PolygonFromText(st_astext(st_buffer(geography(ST_PointFromText('POINT('||st_x(geom)||' '||st_y(geom)||')',4326)), 500 )) ,4326); String sql = "select st_Area(Geography(st_intersection(a.geom,b.geom)))/st_Area(geography(a.geom)) as per100 " + "from sqs.sqs_city a, "+tablename +" b " + "where st_Intersects(a.geom,b.geom) and b."+id+"='"+ storeid+ "' and b.username='"+username +"' and b.status=1" ; String sql = "select ceil(totarea) as totarea,st_asgeojson(b.geom) as geometry, ceil(st_distance(Geography(ST_PointFromText('POINT(" + x + " " + y +")',4326)),Geography(b.geom))) as distance from sqs.sqs_newhouse b " + "where ST_Intersects(ST_PolygonFromText('POLYGON(("+p+"))',4326), b.geom) and " +"dlvydate > '2010-1-1' " + "order by tothh desc " + "limit 10";
学习资源 · PostgreSQL 10.1 手册
http://www.postgres.cn/docs/10/index.html · PostgreSQL 学习手册笔记 https://www.cnblogs.com/stephen-liu74/archive/2012/06/08/2315679.html · PostgreSQL 常用操作总结
https://www.cnblogs.com/kaituorensheng/p/4667160.html#_label3 · PostGIS Reference
https://postgis.net/docs/reference.html 未完待续…
