[英]PSQL - Copy from csv file if column item does not exist
I am trying to import a csv file into the postgres table where I can successfully do so using COPY FROM : 我正在尝试将csv文件导入postgres表,我可以使用COPY FROM成功执行此操作:
import.sql import.sql
\copy myTable FROM '..\CSV_OUTPUT.csv' DELIMITER ',' CSV HEADER;
But that query only adds rows if it is currently not in the database, otherwise it exits with an error. 但是,如果当前不在数据库中,则该查询仅添加行,否则将退出并显示错误。 Key (id)=(#) already exists. 密钥(id)=(#)已经存在。
myTable 为myTable
id | alias | address
------+-------------+---------------
11 | red_foo | 10.1.1.11
12 | blue_foo | 10.1.1.12
CSV_OUTPUT.csv CSV_OUTPUT.csv
id | alias | address
------+-------------+---------------
10 | black_foo | 10.1.1.11
12 | blue_foo | 10.1.1.12
13 | grey_foo | 10.1.1.13
14 | pink_foo | 10.1.1.14
My desired output is to insert the rows from the csv file into postgresql if address does not exist. 我想要的输出是将csv文件中的行插入postgresql(如果地址不存在)。 myTable should contain grey_foo and pink_foo already but not black_foo since its address already exist. myTable应该包含grey_foo和pink_foo但不包含black_foo,因为它的地址已经存在。
What should be the right queries to use in order to achieve this? 为实现这一目标,应该使用哪些正确的查询? Your suggestions and ideas are highly appreciated. 非常感谢您的建议和想法。
Copy the data into a staging table first, and then update your main table ( myTable
) with only the rows with the keys that don't already exist. 首先将数据复制到临时表中,然后仅使用具有尚不存在的键的行更新主表( myTable
)。 For example, assuming you have imported the data into a table named staging
: 例如,假设您已将数据导入名为staging
的表中:
with nw as (
select s.id, s.alias, s.address
from staging as s
left join mytable as m on m.address=s.address
where m.address is null
)
insert into mytable
(id, alias, address)
select id, alias, address
from nw;
If you can upgrade to Postgres 9.5, you could instead use an INSERT
command with the ON CONFLICT DO NOTHING
clause. 如果可以升级到Postgres 9.5,则可以使用带有ON CONFLICT DO NOTHING
子句的INSERT
命令。
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