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tldr/pages/common/q.md
Managor 5305776d45
*: capitalize the first letter after "Note:" (#16226)
Co-authored-by: Machiavelli <145562237+MachiavelliII@users.noreply.github.com>
2025-05-04 05:15:17 +03:00

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q

Execute SQL-like queries on CSV and TSV files. More information: https://harelba.github.io/q.

  • Query a CSV file by specifying the delimiter as ',':

q {{[-d|--delimiter]}} ',' "SELECT * from {{path/to/file}}"

  • Query a TSV file:

q {{[-t|--tab-delimited]}} "SELECT * from {{path/to/file}}"

  • Query file with header row:

q {{[-d|--delimiter]}} {{delimiter}} {{[-H|--skip-header]}} "SELECT * from {{path/to/file}}"

  • Read data from stdin; '-' in the query represents the data from stdin:

{{output}} | q "select * from -"

  • Join two files (aliased as f1 and f2 in the example) on column c1, a common column:

q "SELECT * FROM {{path/to/file}} f1 JOIN {{path/to/other_file}} f2 ON (f1.c1 = f2.c1)"

  • Format output using an output delimiter with an output header line (Note: Command will output column names based on the input file header or the column aliases overridden in the query):

q {{[-D|--output-delimiter]}} {{delimiter}} {{[-O|--output-header]}} "SELECT {{column}} as {{alias}} from {{path/to/file}}"