tldr/pages/common/q.md

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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',' "SELECT * from {{path/to/file}}"

  • Query a TSV file:

q -t "SELECT * from {{path/to/file}}"

  • Query file with header row:

q -d{{delimiter}} -H "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{{delimiter}} -O "SELECT {{column}} as {{alias}} from {{path/to/file}}"