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ÓбíTABLE£¬A,B,CÈýÁС£²éѯ¸Ã±íÊý¾Ý£¬µ±AÁдóÓÚBÁÐʱѡÔñÏÔʾBÁУ¬Èç¹ûCÁдóÓÚBÁÐʱ£¬Ñ¡ÔñÏÔʾCÁС£
Ó¦¸ÃÒªÓõ½ CASE WHEN°É¡£¡£ÓеãÍ·ÌÛÁË¡£ÀÏÊÇ˵ÎÒÉÙЩ¸ö²ÎÊý¡£

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û˵Çå³þ£¬ÊÇORACLEϵÄÓï¾ä¡£ºÃÏñ²»ÄÜÓà case when¡£ÎÒ²»ÖªµÀ¸ÃÔõô×öÁË

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Â¥Ö÷°Ñ´úÂëÌùÉÏ¿´¿´¡£ÓÃcase when ÊÇ¿ÉÒԵġ£

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³É¹¦ÁË¡£¡£¡£¸Õ²Å×Ô¼ºÊÔ³öÀ´ÁË¡£

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SQL code:
select decode(sign(A-B),1,B),decode(sign(C-B),1,C) from table

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SQL code:
--1.case
SELECT CASE
WHEN c > b THEN
c
WHEN b > a THEN
b
ELSE
a
END
from t1;

--2.decode
SELECT decode(sign(c - b), 1, c, decode(sign(b - a), 1, b, a), a) from t1;

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SQL code:

SQL> create table tb(A int,B int, C int);

Table created.

SQL> insert into tb values(3,5,7);

1 row created.

SQL> insert into tb values(7,3,8);

1 row created.

SQL> insert into tb values(4,2,6);

1 row created.

SQL> select * from tb;

A B C
---------- ---------- ----------
3 5 7