SQL選擇：以其他狀態返回特定值

Question

我在postgres中有一個場景，我希望執行兩個字段的簡單劃分。

祝回答返回是1，如果回答爲小於1

SELECT a/b AS Answer 

6/4 = 1.50 
4/6 = 0.66 
4/4 = 1.00 

例如，如果計算上述被用來我想SQL用於第二計算返回值1 。

Answer 1

您可以使用CASE-WHEN

SELECT CASE 
     WHEN ans < 1 
      THEN 1 
     ELSE ans 
     END AS answer 
FROM (
    SELECT a/b::REAL AS ans 
    FROM num1 
    ) t 

sqlfiddle

或

SELECT CASE 
     WHEN a < b 
      THEN 1 
     ELSE a/b::REAL 
     END AS answer 
FROM num1 

sqlfiddle

Answer 2

CREATE table testdata (a int,b int); 
WITH data AS (
    INSERT INTO testdata VALUES (6,4),(4,6),(4,4) 
) 
SELECT a,b, 
    CASE WHEN a/b::REAL < 1 THEN 1 
    ELSE a/b::REAL 
    END 
FROM testdata; 

Answer 3

SELECT GREATEST(a/b, 1) AS Answer