csvsql - Man Page

• Generate a CREATE TABLE SQL statement for a CSV file: csvsql path/to/data.csv
• Import a CSV file into an SQL database: csvsql --insert --db "mysql://user:password@host/database" data.csv
• Run an SQL query on a CSV file: csvsql --query "select * from 'data'" data.csv

tldr.sh

Generate SQL statements for a CSV file or execute those statements directly on a database. In the latter case supports both creating tables and inserting data:

usage: csvsql [-h] [-d DELIMITER] [-t] [-q QUOTECHAR] [-u {0,1,2,3}] [-b]
              [-p ESCAPECHAR] [-z FIELD_SIZE_LIMIT] [-e ENCODING] [-L LOCALE]
              [-S] [--blanks] [--date-format DATE_FORMAT]
              [--datetime-format DATETIME_FORMAT] [-H] [-K SKIP_LINES] [-v]
              [-l] [--zero] [-V]
              [-i {firebird,mssql,mysql,oracle,postgresql,sqlite,sybase,crate}]
              [--db CONNECTION_STRING] [--query QUERY] [--insert]
              [--prefix PREFIX] [--tables TABLE_NAMES] [--no-constraints]
              [--unique-constraint UNIQUE_CONSTRAINT] [--no-create]
              [--create-if-not-exists] [--overwrite] [--db-schema DB_SCHEMA]
              [-y SNIFF_LIMIT] [-I] [--chunk-size NUM]
              [FILE [FILE ...]]

Generate SQL statements for one or more CSV files, or execute those statements
directly on a database, and execute one or more SQL queries.

positional arguments:
  FILE                  The CSV file(s) to operate on. If omitted, will accept
                        input on STDIN.

optional arguments:
  -h, --help            show this help message and exit
  -i {firebird,mssql,mysql,oracle,postgresql,sqlite,sybase,crate}, --dialect {firebird,mssql,mysql,oracle,postgresql,sqlite,sybase,crate}
                        Dialect of SQL to generate. Only valid when --db is
                        not specified.
  --db CONNECTION_STRING
                        If present, a sqlalchemy connection string to use to
                        directly execute generated SQL on a database.
  --query QUERY         Execute one or more SQL queries delimited by ";" and
                        output the result of the last query as CSV. QUERY may
                        be a filename.
  --insert              In addition to creating the table, also insert the
                        data into the table. Only valid when --db is
                        specified.
  --prefix PREFIX       Add an expression following the INSERT keyword, like
                        OR IGNORE or OR REPLACE.
  --tables TABLE_NAMES  A comma-separated list of names of tables to be
                        created. By default, the tables will be named after
                        the filenames without extensions or "stdin".
  --no-constraints      Generate a schema without length limits or null
                        checks. Useful when sampling big tables.
  --unique-constraint UNIQUE_CONSTRAINT
                        A column-separated list of names of columns to include
                        in a UNIQUE constraint.
  --no-create           Skip creating a table. Only valid when --insert is
                        specified.
  --create-if-not-exists
                        Create table if it does not exist, otherwise keep
                        going. Only valid when --insert is specified.
  --overwrite           Drop the table before creating. Only valid when
                        --insert is specified and --no-create is not
                        specified.
  --db-schema DB_SCHEMA
                        Optional name of database schema to create table(s)
                        in.
  -y SNIFF_LIMIT, --snifflimit SNIFF_LIMIT
                        Limit CSV dialect sniffing to the specified number of
                        bytes. Specify "0" to disable sniffing entirely.
  -I, --no-inference    Disable type inference when parsing the input.
  --chunk-size NUM
                        Chunk size for batch insert into the table.
                        Only valid when --insert is specified.

See also: ../common_arguments.

For information on connection strings and supported dialects refer to the SQLAlchemy documentation.

If you prefer not to enter your password in the connection string, store the password securely in a PostgreSQL Password File, a MySQL Options File or similar files for other systems.

NOTE:

Generate a statement in the PostgreSQL dialect:

csvsql -i postgresql examples/realdata/FY09_EDU_Recipients_by_State.csv

Create a table and import data from the CSV directly into PostgreSQL:

createdb test
csvsql --db postgresql:///test --tables fy09 --insert examples/realdata/FY09_EDU_Recipients_by_State.csv

For large tables it may not be practical to process the entire table. One solution to this is to analyze a sample of the table. In this case it can be useful to turn off length limits and null checks with the --no-constraints option:

head -n 20 examples/realdata/FY09_EDU_Recipients_by_State.csv | csvsql --no-constraints --tables fy09

Create tables for an entire folder of CSVs and import data from those files directly into PostgreSQL:

createdb test
csvsql --db postgresql:///test --insert examples/*_converted.csv

If those CSVs have identical headers, you can import them into the same table by using csvstack first:

createdb test
csvstack examples/dummy?.csv | csvsql --db postgresql:///test --insert

Group rows by one column:

csvsql --query "select * from 'dummy3' group by a" examples/dummy3.csv

You can also use CSVSQL to “directly” query one or more CSV files. Please note that this will create an in-memory SQL database, so it won’t be very fast:

csvsql --query  "select m.usda_id, avg(i.sepal_length) as mean_sepal_length from iris as i join irismeta as m on (i.species = m.species) group by m.species" examples/iris.csv examples/irismeta.csv

Concatenate two columns:

csvsql --query "select a || b from 'dummy3'" examples/dummy3.csv

If a column contains null values, you must COALESCE the column:

csvsql --query "select a || COALESCE(b, '') from 'sort_ints_nulls'" --no-inference examples/sort_ints_nulls.csv

Christopher Groskopf

2021, Christopher Groskopf