我将此作为 Informix 问题而不是 Awk 问题来处理。
使用标准的 Informix SQL 命令，您也可以创建一个 CSV 格式的 external table — 但您必须知道您可以使用一种未记录的格式 "DB2"：
DROP TABLE IF EXISTS data_table;
CREATE TABLE data_table
(
part_no INTEGER,
date_part DATETIME YEAR TO SECOND,
history_code VARCHAR(4),
user_id VARCHAR(32),
other_information VARCHAR(64),
pool_no INTEGER
);
INSERT INTO data_table VALUES(100000001, "2010-10-13 12:12:12", "ABCD", "rsmith", "note: Monday, December 10", 101011777);
INSERT INTO data_table VALUES(100000002, "2010-10-21 12:12:12", "GHIJ", "jsmith", NULL, 101011888);
INSERT INTO data_table VALUES(100000002, "2010-10-27 12:12:12", "LMNO", "fevers", "[Mail]", 101011999);
INSERT INTO data_table VALUES(100000003, "2010-11-13 12:12:12", "QXRT", "sjohnson", "note: Tuesday, August 31", 101011111);
DROP TABLE IF EXISTS csv_data;
CREATE EXTERNAL TABLE csv_data
(
part_no INTEGER,
date_part DATETIME YEAR TO SECOND,
history_code VARCHAR(4),
user_id VARCHAR(32),
other_information VARCHAR(64),
pool_no INTEGER
)
USING (FORMAT "DB2", DELIMITER ",", DATAFILES("DISK:/tmp/data/csv_data.csv"));
INSERT INTO csv_data
SELECT part_no, date_part, history_code, user_id, other_information, pool_no
FROM data_table;
/tmp/data/csv_data.csv 的内容如下：
100000001,2010-10-13 12:12:12,"ABCD","rsmith","note: Monday, December 10",101011777
100000002,2010-10-21 12:12:12,"GHIJ","jsmith",,101011888
100000002,2010-10-27 12:12:12,"LMNO","fevers","[Mail]",101011999
100000003,2010-11-13 12:12:12,"QXRT","sjohnson","note: Tuesday, August 31",101011111
UNLOAD 格式转换为 CSV
DB-Access 的默认输出在实践中不容易解析。
在某些有限的情况下可能是可行的，例如您显示的情况，但您最好使用 UNLOAD 格式而不是命令行输出，然后将 UNLOAD 数据格式转换为 CSV。
我有一个执行此操作的 Perl 脚本。它使用 Perl Text::CSV 模块来处理 CSV 格式。它不会假装处理带有列名的第一行； UNLOAD 格式文件中不存在这些。
#!/usr/bin/env perl
#
# @(#)$Id: unl2csv.pl,v 1.3 2018/06/29 20:36:58 jleffler Exp $
#
# Convert Informix UNLOAD format to CSV
use strict;
use warnings;
use Text::CSV;
use IO::Wrap;
my $csv = new Text::CSV({ binary => 1 }) or die "Failed to create CSV handle ($!)";
my $dlm = defined $ENV{DBDELIMITER} ? $ENV{DBDELIMITER} : "|";
my $out = wraphandle(\*STDOUT);
my $rgx = qr/((?:[^$dlm]|(?:\\.))*)$dlm/sm;
# $csv->eol("\r\n");
while (my $line = <>)
{
print "1: $line";
MultiLine:
while ($line eq "\\\n" || $line =~ m/[^\\](?:\\\\)*\\$/)
{
my $extra = <>;
last MultiLine unless defined $extra;
$line .= $extra;
}
my @fields = split_unload($line);
$csv->print($out, \@fields);
}
sub split_unload
{
my($line) = @_;
my @fields;
print "$line";
while ($line =~ $rgx)
{
printf "%d: %s\n", scalar(@fields), $1;
push @fields, $1;
}
return @fields;
}
__END__
=head1 NAME
unl2csv - Convert Informix UNLOAD to CSV format
=head1 SYNOPSIS
unl2csv [file ...]
=head1 DESCRIPTION
The unl2csv program converts a file from Informix UNLOAD file format to
the corresponding CSV (comma separated values) format.
The input delimiter is determined by the environment variable
DBDELIMITER, and defaults to the pipe symbol "|".
It is not assumed that each input line is terminated with a delimiter
(there are two variants of the UNLOAD format, one with and one without
the final delimiter).
=head1 EXAMPLES
Input:
10|12|excessive|cost \|of, living|
20|40|bou\\ncing tigger|grrrrrrrr|
Output:
10,12,"excessive","cost |of, living"
20,40,"bou\ncing tigger",grrrrrrrr
=head1 PRE-REQUISITES
Text::CSV_XS
=head1 AUTHOR
Jonathan Leffler <jonathan.leffler@hcl.com>
=cut
您会使用这样的命令（通过 DB-Access）：
UNLOAD TO "datatable.unl" SELECT * FROM DataTable;
然后运行：
perl unl2csv datatable.unl > datatable.csv
SQLCMD 程序
如果您有我的 SQLCMD 程序（可从软件存储库中的 IIUG 网站获得，并且与 Microsoft 的同名 johnny-come-lately 完全无关），那么您可以直接卸载为 CSV 格式：
sqlcmd -d database -F csv -e 'unload to "data_table.csv" select * from data_table'