Select

Picks and computes columns.

1. select {
2. name = expression,
3. # or
4. column,
5. }
6. # or
7. select !{column}

Examples

1. from employees
2. select name = f"{first_name} {last_name}"

1. SELECT
2. CONCAT(first_name, ' ', last_name) AS name
3. FROM
4. employees

1. from employees
2. select {
3. name = f"{first_name} {last_name}",
4. age_eoy = dob - @2022-12-31,
5. }

1. SELECT
2. CONCAT(first_name, ' ', last_name) AS name,
3. dob - DATE '2022-12-31' AS age_eoy
4. FROM
5. employees

1. from employees
2. select first_name

1. SELECT
2. first_name
3. FROM
4. employees

1. from e=employees
2. select {e.first_name, e.last_name}

1. SELECT
2. first_name,
3. last_name
4. FROM
5. employees AS e

We can use ! to exclude a list of columns. This can operate in two ways:

We use SELECT * EXCLUDE / SELECT * EXCEPT for the columns supplied to select !{} in dialects which support it.
Otherwise, the columns must have been defined prior in the query (unless all of a table’s columns are excluded); for example in another select or a group transform. In this case, we evaluate and specify the columns that should be included in the output SQL.

Some examples:

1. prql target:sql.bigquery
2. from tracks
3. select !{milliseconds, bytes}

1. SELECT
2. *
3. EXCEPT
4. (milliseconds, bytes)
5. FROM
6. tracks

1. from tracks
2. select {track_id, title, composer, bytes}
3. select !{title, composer}

1. SELECT
2. track_id,
3. bytes
4. FROM
5. tracks

1. from artists
2. derive nick = name
3. select !{artists.*}

1. SELECT
2. name AS nick
3. FROM
4. artists

Note that ! is also the NOT operator, so without the tuple it has a different meaning:

1. prql target:sql.bigquery
2. from tracks
3. select !is_compilation

1. SELECT
2. NOT is_compilation
3. FROM
4. tracks