ORA_DECODE

声明

ORA_DECODE(condition, value1, return_val1, value2, return_val2, ... valuen, return_val, omit_val)

说明

ORA_DECODE() 函数功能等同于 Oracle 数据库的 DECODE() 函数功能。

该函数的含义如下：

IF 条件=值1
THEN RETURN(返回值1)
ELSIF 条件=值2
THEN RETURN(返回值2)
......
ELSIF 条件=值n
THEN RETURN(返回值n)
ELSE RETURN(缺省值)
END IF

示例

SELECT * FROM films ORDER BY ORA_DECODE(id,1,'lala',2,'mua');

+------+--------------+-------------+--------+
| id   | release_year | category_id | rating |
+------+--------------+-------------+--------+
|    3 |         2015 |           3 |   9.00 |
|    4 |         2016 |           2 |   8.20 |
|    5 |         2016 |           1 |   8.40 |
|    6 |         2017 |           2 |   7.00 |
|    1 |         2015 |           1 |   8.00 |
|    2 |         2015 |           2 |   8.50 |
+------+--------------+-------------+--------+