(PHP 5 >= 5.3.3, PHP 7, PHP 8)
PDO::pgsqlCopyToFile — Copy data from table into file
$table_name,$filename,$delimiter = "\t",$null_as = "\\\\N",$fields = ?
   Copies data from table into file specified by filename
   using delimiter as fields delimiter and fields list
  
table_nameString containing table name
filenameFilename to export data
delimiter
       Delimiter used in file specified by filename
      
null_asHow to interpret null values
fieldsList of fields to insert
   Returns true on success, 或者在失败时返回 false.