PostgreSQL copy 命令使用示例
PostgreSQL 提供了 copy 命令用于在数据库表与文件之间拷贝数据，通过 copy 命令可以把一个表数据导出到文件中，也可以把文件中的数据导入到表里面。
1. copy 命令语法
COPY table_name [ ( column_name [, ...] ) ] FROM { 'filename' | PROGRAM 'command' | STDIN } [ [ WITH ] ( option [, ...] ) ] [ WHERE condition ] COPY { table_name [ ( column_name [, ...] ) ] | ( query ) } TO { 'filename' | PROGRAM 'command' | STDOUT } [ [ WITH ] ( option [, ...] ) ] where option can be one of: FORMAT format_name FREEZE [ boolean ] DELIMITER 'delimiter_character' NULL 'null_string' HEADER [ boolean ] QUOTE 'quote_character' ESCAPE 'escape_character' FORCE_QUOTE { ( column_name [, ...] ) | * } FORCE_NOT_NULL ( column_name [, ...] ) FORCE_NULL ( column_name [, ...] ) ENCODING 'encoding_name'
