[英]SQL- How to compare two numbers in the same row
如果您的数字有一个最小值(即它们都是正整数),则可以执行以下操作:
Oracle安装程序 :
CREATE TABLE table_name ( ID, name, number1, number2, number3 ) AS
SELECT 1, 'Jane', 6, 7, 1 FROM DUAL UNION ALL
SELECT 2, 'John', 3, 1, NULL FROM DUAL UNION ALL
SELECT 3, 'Jake', NULL, NULL, 5 FROM DUAL;
查询 :
SELECT ID,
NAME,
GREATEST( NVL( NUMBER1, 0 ), NVL( NUMBER2, 0 ), NVL( NUMBER3, 0 ) ) AS biggest
FROM table_name;
输出 :
ID NAME BIGGEST
---------- ---- ----------
1 Jane 7
2 John 3
3 Jake 5
如果没有最小值,则可以执行以下操作:
查询2 :
SELECT ID,
NAME,
CASE WHEN NUMBER1 IS NULL AND NUMBER2 IS NULL AND NUMBER3 IS NULL
THEN NULL
WHEN NUMBER1 IS NULL AND NUMBER2 IS NULL THEN NUMBER3
WHEN NUMBER1 IS NULL AND NUMBER3 IS NULL THEN NUMBER2
WHEN NUMBER2 IS NULL AND NUMBER3 IS NULL THEN NUMBER1
WHEN NUMBER1 IS NULL THEN GREATEST( NUMBER2, NUMBER3 )
WHEN NUMBER2 IS NULL THEN GREATEST( NUMBER1, NUMBER3 )
WHEN NUMBER3 IS NULL THEN GREATEST( NUMBER1, NUMBER2 )
ELSE GREATEST( NUMBER1, NUMBER2, NUMBER3 )
END AS biggest
FROM table_name;
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