在Hive SQL中,沒有直接提供循環(huán)操作的功能
CREATE TEMPORARY TABLE loop_count (
id INT,
value STRING
);
INSERT INTO loop_count (id, value)
VALUES (1, 'value1'), (2, 'value2'), (3, 'value3'), (4, 'value4'), (5, 'value5');
CREATE EXTERNAL TABLE temp_loop (
id INT,
value STRING
)
STORED AS TEXTFILE
LOCATION '/path/to/your/textfile'
TBLPROPERTIES ('EXTERNAL'='TRUE');
SELECT t1.id, t1.value, t2.value AS loop_value
FROM temp_loop t1
MAPJOIN t2 ON (t1.id = t2.id)
DISTRIBUTE BY t1.id
SORT BY t1.id;
這個(gè)查詢將會(huì)輸出以下結(jié)果:
id | value | loop_value
-------------------------
1 | value1 | value1
2 | value2 | value2
3 | value3 | value3
4 | value4 | value4
5 | value5 | value5
請(qǐng)注意,這種方法并不是真正的循環(huán)操作,而是通過將循環(huán)次數(shù)插入到臨時(shí)表中并使用MAPJOIN進(jìn)行分組和排序來實(shí)現(xiàn)的。