Allow parametized views to be dynamic with optional parameters

[gingerwizard]

Currently we have to construct views with static parameters if we want to reuse them across many filters e.g.

CREATE VIEW sold_by_duration AS
SELECT
   duration,
   count() AS value
FROM default.uk_price_paid
WHERE ((postcode1 = {_postcode:String}) OR (district = {_district:String}) OR (town = {_town:String}))
GROUP BY duration


SELECT *
FROM sold_by_duration(_postcode = 'SL4', _district = 'X', _town = 'X')

Proposal is to allow a column name to be passed e.g.

CREATE VIEW sold_by_duration AS
SELECT
   duration,
   count() AS value
FROM default.uk_price_paid
WHERE _column:Column = {_value:String} 
GROUP BY duration

SELECT *
FROM sold_by_duration(_column = 'postcode1', _value = 'SL4')

Alternative and maybe complementary is to allow parameters to be optional - they will in turn be optimized away. This is more challenging obviously i.e.

SELECT *
FROM sold_by_duration(_postcode = 'SL4')

becomes

SELECT
   duration,
   count() AS value
FROM default.uk_price_paid
WHERE postcode1 = 'SL4'
GROUP BY duration

[igoichuk]

Would this help? https://clickhouse.com/docs/en/sql-reference/syntax#defining-and-using-query-parameters
It works to make columns parameters.

If the query parameter represents the name of a database, table, function or other identifier, use Identifier for its type. For example, the following query returns rows from a table named uk_price_paid:

SET param_mytablename = "uk_price_paid";
SELECT * FROM {mytablename:Identifier};