DeltaQuery.Query (DeltaQuery v0.2.3)

Composable query builder for Delta Sharing tables.

Example

"books"
|> Query.new()
|> Query.where("library_id = 100")
|> Query.select(["book_id", "title"])
|> Query.execute!()
|> Results.to_rows()

For post-query operations (joins, filtering, conversion to rows), see DeltaQuery.Results.

Summary

Types

t()

Functions

execute(query, opts \\ [])

Execute the query and return results.

execute!(query, opts \\ [])

Execute the query and return results, raising on error.

limit(query, n)

Set a limit hint for the query.

new(table)

Create a new query for the given table.

select(query, columns)

Select specific columns to return.

where(query, filter)

Add a filter predicate to the query.

Types

t()

@type t() :: %DeltaQuery.Query{
  columns: [String.t()] | nil,
  filters: [String.t()],
  limit: pos_integer() | nil,
  table: String.t()
}

Functions

execute(query, opts \\ [])

@spec execute(
  t(),
  keyword()
) :: {:ok, DeltaQuery.Results.t()} | {:error, term()}

Execute the query and return results.

Options

:config - A DeltaQuery.Config struct or keyword options for configuration. If not provided, configuration is read from application environment.

Returns {:ok, %Results{}} on success or {:error, reason} on failure.

Examples

{:ok, result} =
  "books"
  |> Query.new()
  |> Query.select(["book_id", "title"])
  |> Query.execute()

result.dataframe        #=> %Explorer.DataFrame{...}
result.files_processed  #=> 5
result.total_files      #=> 5

# With explicit config
config = DeltaQuery.Config.new!(endpoint: "...", bearer_token: "...", share: "my_share")
{:ok, result} = Query.execute(query, config: config)

execute!(query, opts \\ [])

@spec execute!(
  t(),
  keyword()
) :: DeltaQuery.Results.t()

Execute the query and return results, raising on error.

Returns %Results{} on success, raises on failure.

Examples

"books"
|> Query.new()
|> Query.where("library_id = 100")
|> Query.execute!()
|> Results.to_rows()

limit(query, n)

@spec limit(t(), pos_integer()) :: t()

Set a limit hint for the query.

Note: This is a hint to the Delta Sharing server and may not be strictly enforced. Calling multiple times overwrites the previous limit.

Examples

"books"
|> Query.new()
|> Query.limit(100)

new(table)

@spec new(String.t()) :: t()

Create a new query for the given table.

Examples

iex> DeltaQuery.Query.new("books")
%DeltaQuery.Query{table: "books"}

select(query, columns)

@spec select(t(), [String.t()]) :: t()

Select specific columns to return.

If not called, all columns are returned. Calling multiple times overwrites previous selections.

Examples

"books"
|> Query.new()
|> Query.select(["book_id", "title", "author"])

where(query, filter)

@spec where(t(), String.t()) :: t()

Add a filter predicate to the query.

Predicates use SQL-like syntax: column operator value

Supported operators: =, !=, >, <, >=, <=

Examples

"books"
|> Query.new()
|> Query.where("library_id = 100")
|> Query.where("genre = 'Fiction'")