Wildcards

Enables to query multiple tables at once using concise SQL statements.

Them are just representation of union of all the tables matching a particular wildcard espression.

Can be used for tables with:

  • similar schema
  • same prefix

"alt"

Practical example

If having a dataset containing tables with the same schema for every year. say:

weather2000, weather2001, ... , weather2021

you can use

SELECT ...
FROM `dataset.weather200`

to get the union from years 2000 to 2009

Filtering by suffix

SELECT ...
FROM <wildcard>
WHERE _TABLE_SUFFIX = <wanted suffix>

Limitations

  1. Supports Big Query storage only. Are not allowed:.
    • External tables
    • Views, even if in a list of tables
  2. Chached results are not supported. Every query will be billed
  3. Can't be used in Insert/delete/update statements. But it is possible to use wildcards in the WHERE