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}}"`