比較列和重復數據消除

請看下面的一個表格，我想創建一個不同的電話號碼列表，排名組號碼需要采取優先級下降1-4。該示例應導致ID 4，9，10（突出顯示為紅色x）被刪除，因為他們共享重復的電話號碼，但在一個較低的優先級組。

我已經嘗試了很多步驟來實現這一點，并創建了一個代理密鑰，但我希望有人能告訴我如何在一個步驟中實現這一點，以提高效率（并提高我的SQL）。

在SAS9中，我有一個coalescec函數，我可以在其中創建一個新變量并指示優先級-但我知道SQL中沒有這樣的函數。

https://documentation.sas.com/doc/en/vdmmlcdc/8.1/ds2ref/n0crpo0xd76wb3n1poba9wmu1a6q.htm

請參見下面SQL中的模擬數據

    CREATE TABLE MT_TEMP_TEL2 (
  ID INT NOT NULL,
  GROUP INT NOT NULL,
  TEL1 VARCHAR(11),
  TEL2 VARCHAR(11),
  TEL3 VARCHAR(11),
  TEL4 VARCHAR(11)
);

INSERT INTO MT_TEMP_TEL2
VALUES 
  (1,4,"79000000000","","",""),
  (2,1,"12111111111","79999999999","",""),
  (3,1,"","13842222222","",""),
  (4,2,"","","78888888888","12111111111"),
  (5,3,"","73333333333","",""),
  (6,1,"15278888888","","",""),
  (7,2,"","","71111111111",""),
  (8,4,"","13843333333","","72222222222"),
  (9,4,"","73333333333","",""),
  (10,3,"75555555555","","12155555555","13842222222");

這是如上所述的預期結果，我們現在刪除了第4、9和10行