从 Snowflake SQL 程序返回表格数据

Question

I'm trying to write a stored procedure that will return the results of a complex query:

CREATE OR REPLACE PROCEDURE sp_partition_ohlc(symbol VARCHAR(10), 
                                              from_time NUMERIC(20, 0), 
                                              til_time NUMERIC(20, 0),  
                                              step_time NUMERIC(20, 0))
    RETURNS TABLE()
    LANGUAGE SQL
    AS
    $$
    BEGIN
        SELECT 
            :step_time * bucket AS t,
            SUM(T.volume) AS v,
            MAX(T.open) AS o,
            MAX(T.close) AS c,
            MAX(T.highlow) AS h,
            MIN(T.highlow) AS l,
            v * (h + l + c) / 3 AS wv,
            COUNT(*) AS n
        FROM (
            SELECT
                FLOOR(T.sip_timestamp / :step_time) AS bucket,
                cta_calc(T.size, T.conditions, 'VOLUME') AS volume,
                cta_calc(T.price, T.conditions, 'HIGHLOW') AS highlow,
                IFF(ROW_NUMBER() OVER (PARTITION BY bucket ORDER BY T.sip_timestamp) = 1, T.price, NULL) AS open,
                LAST_VALUE(cta_calc(T.price, T.conditions, 'LAST')) 
                    IGNORE NULLS OVER (PARTITION BY bucket ORDER BY T.sip_timestamp) AS close
            FROM trades AS T
            WHERE 
                T.symbol = :symbol AND 
                T.sip_timestamp >= :from_time AND
                T.sip_timestamp < :til_time) AS T
        GROUP BY bucket
        ORDER BY bucket;
    END
    $$

This compiles properly but, if I try to run it:

CALL sp_partition_ohlc('NTAP', 1640995200000000000, 1672531200000000000, 3600000000000)

I get the following error:

092222 (P0000): SQL compilation error: stored procedure is missing a return statement

From this, I understand that I should have a RETURN in front of my outer SELECT statement. However, when I modify the procedure thus, it fails to compile with this error:

Syntax error: unexpected 'SELECT'. (line 7) syntax error line 4 at position 23 unexpected '*'. (line 7)

I'm not sure what this error is telling me as, when I run the query by itself, it returns results. I assume I'm doing something wrong in setting up the procedure but I'm not sure what it is from the associated documentation, here . Any help would be appreciated.

Answer 1

It is not a matter of just putting a return in there:

you more want to follow a pattern like:

create or replace procedure get_top_sales()
returns table (sales_date date, quantity number)
language sql
as
declare
  res resultset default (select sales_date, quantity from sales order by quantity desc limit 10);
begin
  return table(res);
end;

here the res is a declared as the result set, which is the SQL to run, so you can access those, and then it is returned as a table via table(res) and the type of the res matches the return type of the function returns table (sales_date date, quantity number) , so for your function you would need to alter this also.

so something like (I have not run):

CREATE OR REPLACE PROCEDURE sp_partition_ohlc(symbol VARCHAR(10), 
                                              from_time NUMERIC(20, 0), 
                                              til_time NUMERIC(20, 0),  
                                              step_time NUMERIC(20, 0))
    RETURNS TABLE(t int, v float, o float, c float, h float, l float, wv float, n int) /* guessed types */
    LANGUAGE SQL
    AS
    $$
    DECLARE
        res resultset;
    BEGIN
    
        let res := (
            SELECT 
                :step_time * bucket AS t,
                SUM(T.volume) AS v,
                MAX(T.open) AS o,
                MAX(T.close) AS c,
                MAX(T.highlow) AS h,
                MIN(T.highlow) AS l,
                v * (h + l + c) / 3 AS wv,
                COUNT(*) AS n
            FROM (
                SELECT
                    FLOOR(T.sip_timestamp / :step_time) AS bucket,
                    cta_calc(T.size, T.conditions, 'VOLUME') AS volume,
                    cta_calc(T.price, T.conditions, 'HIGHLOW') AS highlow,
                    IFF(ROW_NUMBER() OVER (PARTITION BY bucket ORDER BY T.sip_timestamp) = 1, T.price, NULL) AS open,
                    LAST_VALUE(cta_calc(T.price, T.conditions, 'LAST')) 
                        IGNORE NULLS OVER (PARTITION BY bucket ORDER BY T.sip_timestamp) AS close
                FROM trades AS T
                WHERE 
                    T.symbol = :symbol AND 
                    T.sip_timestamp >= :from_time AND
                    T.sip_timestamp < :til_time) AS T
            GROUP BY bucket
            ORDER BY bucket
        );
        
        return table(res);
    END
    $$