使用 SQL Server 中的 CTAS 将数据从具有不同列名的源映射到现有 SQL 表

Question

Scenario:

Is source table SourceData (Name, Number, Date)

Is existing table ProdData (ProdName, ProdNumber, CreatedDate)

Requirement:

Dont import from source if already exists in prod data!!!

Import rows from source to prod data, keep existing rows, append new ones, map columns like:

• Name -> ProdName
• Number -> ProdNumber
• Date -> CreatedDate ( IF Date NULL add SystemDate time )

Output data example:

SourceData

Name | Number | Date
-----+--------+------ 
A    | 1      | 2012
B    | 2      | NULL

ProdData

ProdName | ProdNumber | CreatedDate
---------+------------+------------
Existing |    123     | 2018
A        |    1       | 2012    
B        |    2       | 2020

Answer 1

Would something like this fit your needs?

INSERT ProdData (ProdName, ProdNumber, CreatedDate)
SELECT 
    SourceData.name as "ProdName",
    SourceData.Number as "ProdNumber",
    NVL(SourceData.Date,to_date(sysdate,'YYYY') as "CreatedDate"
FROM 
    SourceData
WHERE 
    NOT EXISTS (SELECT
                    1 
                FROM 
                    ProdData PD2 
                WHERE 
                    PD2.ProdName = SourceData.name
                    and PD2.ProdNumber = SourceData.Number
                    and NVL(PD2.CreatedDate,to_date(sysdate,'YYYY') = nvl(SourceData.Date,to_date(sysdate,'YYYY');

Another alternate option may be something like:

CREATE TABLE ProdData_new
WITH
    (
      DISTRIBUTION = HASH(ProdName)
    , CLUSTERED INDEX (ProdNumber)
    )
AS
SELECT 
      pdold.ProdName AS ProdName
    , pdold.ProdNumber AS ProdNumber
    , NVL(pdold.CreatedDate,to_date(sysdate,'YYYY')) AS CreatedDate
FROM      
    ProdData AS pdold

UNION 

SELECT 
      sdold.name AS ProdName
    , sdold.Number AS ProdNumber
    , NVL(sdold.Date,to_date(sysdate,'YYYY') AS CreatedDate
FROM 
    SourceData AS sdold
;

--Optional Renaming of old tables
--RENAME OBJECT ProdData TO ProdData_old;
--RENAME OBJECT SourceData TO SourceData_old;
--RENAME OBJECT ProdData_new TO ProdData;
--DROP TABLE ProdData_old;
--DROP TABLE SourceData_old;

Or possibly something more like:

CREATE TABLE ProdData_new
    ( ProdName NVARCHAR NOT NULL 
    , ProdNumber INT NOT NULL
    , CreatedDate INT NOT NULL)
WITH
    ( DISTRIBUTION = HASH(ProdName)
    , CLUSTERED INDEX (ProdNumber) )
AS
SELECT 
      pdold.ProdName AS ProdName
    , pdold.ProdNumber AS ProdNumber
    , NVL(pdold.CreatedDate,to_date(sysdate,'YYYY')) AS CreatedDate
FROM      
    ProdData AS pdold

UNION 

SELECT 
      sdold.name AS ProdName
    , sdold.Number AS ProdNumber
    , NVL(sdold.Date,to_date(sysdate,'YYYY') AS CreatedDate
FROM 
    SourceData AS sdold
;

--Optional Renaming of old tables
--RENAME OBJECT ProdData TO ProdData_old;
--RENAME OBJECT SourceData TO SourceData_old;
--RENAME OBJECT ProdData_new TO ProdData;
--DROP TABLE ProdData_old;
--DROP TABLE SourceData_old;

This is all somewhat guess work without knowing what you have tried, your specific syntax and your DB_Schema_Table setup.