flowmachine.core.join¶
Class Join¶
Join(
left,
right,
on_left,
on_right=None,
how="inner",
left_append="",
right_append="",
)
Class that results when joining two queries. Don't usually call this directly, instead use the join method of query.
Attributes¶
Parameters¶
-
left
:Query
Query object to join on.
-
right
:Query
Query object to join on.
-
on_left
:list
ofstr
,str
Name of the column on the left table on which to join, if a list will join on the fact that each field is equal
-
on_right
:optional
,str
Name of the column on the right table on which to join, if not specified will default to the same as on_left, if a list must be the same length as on_left.
-
how
:str
, default'inner'
The method by which to join. Based on the methods provided by postgres. These can be:'inner', 'left outer', 'right outer' and 'full outer'.
-
left_append
:str
, default''
Text with which to append the columns from the left table. Note that the column given by 'on_left' will not be appended to.
-
right_append
:str
, default''
Text with which to append the columns from the left table.
Note
This is not a full implementation of the postgres join api. It assumes joining by matching columns from table1 and table2. The user can construct more complex custom joins by hand.
Methods¶
_select_targets¶
_select_targets
Return a list of the SELECT targets for use in _make_query
Returns¶
-
typing.List[str]
List of columns to include
cache¶
cache
Returns¶
-
bool
True is caching is switched on.
column_names¶
column_names
Returns the column names.
Returns¶
-
typing.List[str]
List of the column names of this query.
column_names_as_string_list¶
column_names_as_string_list
Get the column names as a comma separated list
Returns¶
-
str
Comma separated list of column names
dependencies¶
dependencies
Returns¶
-
set
The set of queries which this one is directly dependent on.
fully_qualified_table_name¶
fully_qualified_table_name
Returns a unique fully qualified name for the query to be stored as under the cache schema, based on a hash of the parameters, class, and subqueries.
Returns¶
-
str
String form of the table's fqn
index_cols¶
index_cols
A list of columns to use as indexes when storing this query.
Returns¶
-
ixen
:list
By default, returns the location columns if they are present and self.spatial_unit is defined, and the subscriber column.
Examples¶
daily_location("2016-01-01").index_cols
[['name'], '"subscriber"']
is_stored¶
is_stored
Returns¶
-
bool
True if the table is stored, and False otherwise.
query_id¶
query_id
Generate a uniquely identifying hash of this query, based on the parameters of it and the subqueries it is composed of.
Returns¶
-
str
query_id hash string
query_state¶
query_state
Return the current query state.
Returns¶
-
QueryState
The current query state
query_state_str¶
query_state_str
Return the current query state as a string
Returns¶
-
str
The current query state. The possible values are the ones defined in
flowmachine.core.query_state.QueryState
.
table_name¶
table_name
Returns a uniquename for the query to be stored as, based on a hash of the parameters, class, and subqueries.
Returns¶
-
str
String form of the table's fqn