Javascript 存储过程雪花

Question

1. I am working on SP which will look for table name defined in ARRAY across all database
2. create view by union on same table name
3. For example for Table A if present in DB 1 and DB 2 then create view by selecting records from both the db

create or replace procedure PROC_1()
  returns VARCHAR -- return final create statement
  language javascript
  as     
$$
    //given two db for testing
    var get_databases_stmt = "SELECT DATABASE_NAME FROM SNOWFLAKE.INFORMATION_SCHEMA.DATABASES WHERE DATABASE_NAME='TERRA_DB' OR DATABASE_NAME='TERRA_DB_2'"
    var get_databases_stmt = snowflake.createStatement({sqlText:get_databases_stmt });
    var databases = get_databases_stmt.execute();
    var row_count = get_databases_stmt.getRowCount();
    var rows_iterated = 0;
    //table on which view will be created       
    var results_table=['STAGE_TABLE','JS_TEST_TABLE];
    var results_db=[];
    while (databases.next())  {
        var database_name = databases.getColumnValue(1);
        //rows_iterated += 1;
        for (let j = 0; j < results_table.length; j++){
            var stmt="CREATE OR REPLACE VIEW  TERRA_DB.TERRA_SCHEMA.ALL_"+results_table[j]+" AS \n";
            stmt += "SELECT * FROM "+database_name+".TERRA_SCHEMA." + results_table[j]
            if (rows_iterated < row_count){
                stmt += " UNION ALL";
            }
            ++rows_iterated;
        }
    }
    //var sql = snowflake.createStatement({sqlText:stmt});
    //var res =sql.execute();
    return stmt;
$$;

call PROC_1();  

Note:- code provided above is creating view by selecting data from one db only, ideally it should select from both db's. Any help will be appreciated!! I am new to JS SP

Answer 1

SQL is expressive enough to achieve it(no loops are necessary).

Using Snowflake Scripting and single query based on ACCOUNT_USAGE.TABLES (the account_usage views have latency):

CREATE OR REPLACE PROCEDURE PROC1()
RETURNS TEXT
LANGUAGE SQL
AS
DECLARE
  sql TEXT;
  schema_name    TEXT := 'TERRA_SCHEMA';
  database_names ARRAY := ARRAY_CONSTRUCT('TERRA_DB', 'TERRA_DB_2');
  table_names    ARRAY := ARRAY_CONSTRUCT('STAGE_TABLE','JS_TEST_TABLE');
BEGIN
  SELECT
    CONCAT('BEGIN',
    LISTAGG(CONCAT('\nCREATE OR REPLACE VIEW TERRA_DB.TERRA_SCHEMA.ALL_'
                   , T.TABLE_NAME, ' AS\n',
                    LISTAGG(CONCAT('SELECT * FROM ', T.TABLE_CATALOG, '.'
                           , T.TABLE_SCHEMA ,'.', T.TABLE_NAME), ' UNION ALL\n')
                    , ';')) OVER(),'\nEND;')  AS query
  INTO sql
  FROM SNOWFLAKE.ACCOUNT_USAGE.TABLES AS T
  WHERE T.DELETED IS NULL
    AND T.TABLE_SCHEMA  ILIKE :schema_name
    AND T.TABLE_NAME    IN (SELECT VALUE FROM TABLE(FLATTEN(INPUT=>:table_names)))
    AND T.TABLE_CATALOG IN (SELECT VALUE FROM TABLE(FLATTEN(INPUT=>:database_names)))
  GROUP BY T.TABLE_NAME
  LIMIT 1;

  EXECUTE IMMEDIATE sql;
  RETURN sql;
END;

Call:

CALL PROC1();

Output:

BEGIN
CREATE OR REPLACE VIEW TERRA_DB.TERRA_SCHEMA.ALL_STAGE_TABLE AS
SELECT * FROM TERRA_DB.TERRA_SCHEMA.STAGE_TABLE UNION ALL
SELECT * FROM TERRA_DB_2.TERRA_SCHEMA.STAGE_TABLE;
CREATE OR REPLACE VIEW TERRA_DB.TERRA_SCHEMA.ALL_JS_TEST_TABLE AS
SELECT * FROM TERRA_DB.TERRA_SCHEMA.JS_TEST_TABLE;
END;

---

Inline query - the clue of this solution is to generate CREATE VIEW based on metadata table:

inner aggregate LISTAGG() - (multiple tables per create view with withe the same table name)

outer analytical LISTAGG() OVER() - combine multiple create view into single output inside begin... end block(required by execute immediate )

SELECT
    CONCAT('BEGIN',
    LISTAGG(CONCAT('\nCREATE OR REPLACE VIEW TERRA_DB.TERRA_SCHEMA.ALL_'
                   , T.TABLE_NAME, ' AS\n',
                    LISTAGG(CONCAT('SELECT * FROM ', T.TABLE_CATALOG, '.'
                           , T.TABLE_SCHEMA ,'.', T.TABLE_NAME), ' UNION ALL\n')
                    , ';')) OVER(),'\nEND;')  AS query
FROM SNOWFLAKE.ACCOUNT_USAGE.TABLES AS T
WHERE T.DELETED IS NULL
  AND T.TABLE_SCHEMA  ILIKE 'TERRA_SCHEMA'
  AND T.TABLE_NAME    IN (SELECT VALUE FROM TABLE(FLATTEN(INPUT=>
                           ARRAY_CONSTRUCT('STAGE_TABLE','JS_TEST_TABLE'))))
  AND T.TABLE_CATALOG IN (SELECT VALUE FROM TABLE(FLATTEN(INPUT=>
                            ARRAY_CONSTRUCT('TERRA_DB', 'TERRA_DB_2'))))
GROUP BY T.TABLE_NAME
LIMIT 1;

Sample input:

CREATE OR REPLACE DATABASE TERRA_DB;
CREATE OR REPLACE SCHEMA TERRA_SCHEMA;

CREATE OR REPLACE TABLE STAGE_TABLE(col TEXT, col2 INT) AS
SELECT 'TERRA_DB.TERRA_ALL.STAGE_TABLE', 1;

CREATE OR REPLACE TABLE TERRA_SCHEMA.JS_TEST_TABLE(col TEXT, col2 INT) AS
SELECT 'TERRA_DB.TERRA_ALL.JS_TEST_TABLE', 1;

CREATE OR REPLACE DATABASE TERRA_DB_2;
CREATE OR REPLACE SCHEMA TERRA_SCHEMA;

CREATE OR REPLACE TABLE TERRA_SCHEMA.STAGE_TABLE(col TEXT, col2 INT) AS
SELECT 'TERRA_DB_2.TERRA_ALL.STAGE_TABLE', 2;

Test of created view:

SELECT *
FROM TERRA_DB.TERRA_SCHEMA.ALL_STAGE_TABLE;

Output: