Javascript 存儲過程雪花

Question

1. 我正在研究 SP，它將在所有數據庫中查找在 ARRAY 中定義的表名
2. 通過聯合在同一個表名上創建視圖
3. 例如，對於表 A，如果存在於 DB 1 和 DB 2 中，則通過從兩個數據庫中選擇記錄來創建視圖

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();  

注意：- 上面提供的代碼僅通過從一個數據庫中選擇數據來創建視圖，理想情況下，它應該從兩個數據庫中選擇 select。 任何幫助將不勝感激！！ 我是 JS SP 的新手

Answer 1

SQL 的表現力足以實現它（不需要循環）。

使用雪花腳本和基於ACCOUNT_USAGE.TABLES的單個查詢（account_usage 視圖有延遲）：

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;

稱呼：

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;

---

內聯查詢 - 這個解決方案的線索是根據元數據表生成CREATE VIEW ：

內部聚合 LISTAGG() -（每個創建視圖具有相同表名的多個表）

外部分析 LISTAGG() OVER() - 將多個創建視圖組合到單個 output 內begin... end塊（需要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;

樣本輸入：

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;

創建視圖的測試：

SELECT *
FROM TERRA_DB.TERRA_SCHEMA.ALL_STAGE_TABLE;

Output：