hive insert table的寫法

hive官方文檔中這樣描述將數據從一個表中插入到另一個表中

hive> FROM invites a INSERT OVERWRITE TABLE events SELECT a.bar, count(*) WHERE a.foo > 0 GROUP BY a.bar;

hive> INSERT OVERWRITE TABLE events SELECT a.bar, count(*) FROM invites a WHERE a.foo > 0 GROUP BY a.bar; 

The keyword 'overwrite' signifies that existing data in the table is deleted.
If the 'overwrite' keyword is omitted, data files are appended to existing data sets.

但若省略overwrite，則會報如下錯：

hive> INSERT TABLE events SELECT a.bar, count(*) FROM invites a WHERE a.foo > 0 GROUP BY a.bar;  
FAILED: ParseException line 1:0 cannot recognize input near 'insert' 'table' 'events' in insert clause

省略overwirite的正確寫法是：

hive> INSERT INTO TABLE events SELECT a.bar, count(*) FROM invites a WHERE a.foo > 0 GROUP BY a.bar;  

就這麼簡單，官方文檔中有這樣的寫法，可能不會引起大家的注意：

hive> LOAD DATA LOCAL INPATH './examples/files/kv2.txt' OVERWRITE INTO TABLE invites PARTITION (ds='2008-08-15'); 

hive> LOAD DATA LOCAL INPATH './examples/files/kv3.txt' OVERWRITE INTO TABLE invites PARTITION (ds='2008-08-08'); 

這是帶了into的，但將insert將在行首，沒有加into的寫法，所以一開始我也很迷糊。

官方文檔地址：https://cwiki.apache.org/confluence/display/Hive/GettingStarted#GettingStarted-InstallationandConfiguration