pg 根据sql导出数据 copy命令导出导入

1. 创建文件,并设置777权限

cd /home/popo
touch export.csv
chmod 777 export.csv

2. 使用超级账号postgres进入psql
   psql -U postgres -d popo -p 5432

3. 导出命令
   copy (select * from student where age > 18) to '/home/popo/export.csv' with csv header;
   若导出整个表, 用表名替换sql语句即可
   copy student to '/home/popo/export.csv' with csv header;

4. copy命令还能用于导入数据到表中, 如:
   copy student from '/data/test_data.csv' WITH delimiter ',' CSV HEADER encoding 'utf-8';