qhs

SQL queries on CSV and TSV files

This is a Haskell implementation of q command.

Installation

Homebrew

brew install itchyny/tap/qhs

Build with stack

stack install qhs

Usage

In the beginning, qhs [QUERY] is the basic usage.

 $ wc * > wc_out.txt
 $ qhs "SELECT * FROM ./wc_out.txt"
66 471 3131 File.hs
118 649 4962 Main.hs
61 258 2346 Option.hs
51 366 2564 Parser.hs
45 273 1769 SQL.hs
341 2017 14772 total

You can specify the file name for the table name. The column names are automatically assigned as c1, c2 and so on.

 $ qhs "SELECT c4,c1 FROM ./wc_out.txt WHERE c4 <> 'total' ORDER BY c1 DESC"
Main.hs 118
File.hs 66
Option.hs 61
Parser.hs 51
SQL.hs 45

The qhs command can read the table from the standard input as well.

 $ wc * | qhs "SELECT c4,c1 FROM - WHERE c4 <> 'total' ORDER BY c1 DESC"
Main.hs 118
File.hs 66
Option.hs 61
Parser.hs 51
SQL.hs 45

You can use -H flag to make qhs regard the head line as the row of column names.

 $ cat basic.csv
foo,bar,baz
a0,1,a2
b0,3,b2
c0,,c2
 $ qhs -H "SELECT * FROM basic.csv WHERE bar IS NOT NULL"
a0 1 a2
b0 3 b2

You can use the basic SQL operations; GROUP BY, ORDER BY, LIMIT and COUNT(*).

 $ ps -ef | qhs -H -O "SELECT UID,COUNT(*) cnt FROM - GROUP BY UID ORDER BY cnt DESC LIMIT 3"
UID cnt
503 102
0 86
89 3

You can also use other SQL operations like JOIN, UNION and sub-query. The command helps you deal with multiple CSV files.

Please refer to qhs --help for further options. The command respects the behaviour of the original q command.

 $ qhs --help
qhs - SQL queries on CSV and TSV files

Usage: qhs [-H|--skip-header] [-O|--output-header] [-d|--delimiter DELIMITER]
           [-t|--tab-delimited] [-p|--pipe-delimited]
           [-D|--output-delimiter OUTPUT_DELIMITER] [-T|--tab-delimited-output]
           [-P|--pipe-delimited-output] [-k|--keep-leading-whitespace]
           [-z|--gzipped] [-q|--query-filename QUERY_FILENAME] [QUERY]

Available options:
  -h,--help                Show this help text
  -v,--version             Show the version of the command.
  -H,--skip-header         Skip the header row for row input and use it for
                           column names instead.
  -O,--output-header       Output the header line.
  -d,--delimiter DELIMITER Field delimiter. If not specified, automatically
                           detected.
  -t,--tab-delimited       Same as -d $'\t'.
  -p,--pipe-delimited      Same as -d '|'.
  -D,--output-delimiter OUTPUT_DELIMITER
                           Field delimiter for output. If not specified, the
                           argument of -d DELIMITER is used.
  -T,--tab-delimited-output
                           Same as -D $'\t'.
  -P,--pipe-delimited-output
                           Same as -D '|'.
  -k,--keep-leading-whitespace
                           Keep leading whitespace in values. The leading
                           whitespaces are stripped off by default.
  -z,--gzipped             Assuming the gzipped input.
  -q,--query-filename QUERY_FILENAME
                           Read query from the provided filename.

Author

itchyny (https://github.com/itchyny)

License

This software is released under the MIT License, see LICENSE.