1.DML
1.1导入数据
1.1.1 Load方式导入数据
LOAD DATA [LOCAL] INPATH 'filepath' [OVERWRITE] INTO TABLE tablename [PARTITION (partcol1=val1, partcol2=val2 ...)]
LOAD DATA [LOCAL] INPATH 'filepath' [OVERWRITE] INTO TABLE tablename [PARTITION (partcol1=val1, partcol2=val2 ...)] [INPUTFORMAT 'inputformat' SERDE 'serde'] (3.0 or later)
示例：
//从本地导入数据
load data local inpath 'path' into|overwrite table table_name [partition (partcol=val,.......)]
//从HDFS导入数据
load data inpath 'Hdfs_path' into|overwrite table table_name [partition (partcol=val,.......)]
注意： into表示在表后追加，overwrite表示在覆盖。从本地导入数据文件被执行copy操作，从HDFS导入数据文件被执行move操作（因为hdfs文件存在副本的原因）
1.1.2 insert into 的方式
Standard syntax:
INSERT OVERWRITE TABLE tablename1 [PARTITION (partcol1=val1, partcol2=val2 ...) [IF NOT EXISTS]] select_statement1 FROM from_statement;
INSERT INTO TABLE tablename1 [PARTITION (partcol1=val1, partcol2=val2 ...)] select_statement1 FROM from_statement;
Hive extension (multiple inserts):
FROM from_statement
INSERT OVERWRITE TABLE tablename1 [PARTITION (partcol1=val1, partcol2=val2 ...) [IF NOT EXISTS]] select_statement1
[INSERT OVERWRITE TABLE tablename2 [PARTITION ... [IF NOT EXISTS]] select_statement2]
[INSERT INTO TABLE tablename2 [PARTITION ...] select_statement2] ...;
FROM from_statement
INSERT INTO TABLE tablename1 [PARTITION (partcol1=val1, partcol2=val2 ...)] select_statement1
[INSERT INTO TABLE tablename2 [PARTITION ...] select_statement2]
[INSERT OVERWRITE TABLE tablename2 [PARTITION ... [IF NOT EXISTS]] select_statement2] ...;
Hive extension (dynamic partition inserts):
INSERT OVERWRITE TABLE tablename PARTITION (partcol1[=val1], partcol2[=val2] ...) select_statement FROM from_statement;
INSERT INTO TABLE tablename PARTITION (partcol1[=val1], partcol2[=val2] ...) select_statement FROM from_statement;
示例：
//假设psn存在 id，name .likes字段，psn1，psn2表存在
//方式1
FROM psn
INSERT OVERWRITE TABLE psn1
SELECT id,name
insert into psn2
select id,likes
用途：选取一个表的某些字段的值，存到一个已经存在的表中或多个表中（此表字段属性必须和插入的值的属性一样）。
//方式2
FROM psn
INSERT OVERWRITE TABLE psn1
SELECT id,name
FROM psn
insert into psn2
select id,likes
注意:方式1和2表达的意思虽然相同，但执行过程却不同。这两种方式执行都会执行mr任务。方式1，读取一次表数据，执行一次mr任务。方式2，读取两次表数据，执行两次mr任务。方式1效率更高，更常使用。我们在执行任务时，尽量减少IO（磁盘IO或是网络IO）
1.2 更新（update）和删除（delete）
FAILED: SemanticException [Error 10294]: Attempt to do update or delete using transaction manager that does not support these operations.
hive不能单独使用update和delete操作。
必须设置这些配置参数以打开Hive中的事务支持。
hive官网事务介绍与配置
hive支持事务，但是一般不会使用。
2.SerDe
Hive SerDe - Serializer and Deserializer
--------SerDe 用于做序列化和反序列化。
--------构建在数据存储和执行引擎之间，对两者实现解耦。
--------Hive通过ROW FORMAT DELIMITED以及SERDE进行内容的读写。
row_format
: DELIMITED [FIELDS TERMINATED BY char [ESCAPED BY char]] [COLLECTION ITEMS TERMINATED BY char]
[MAP KEYS TERMINATED BY char] [LINES TERMINATED BY char]
[NULL DEFINED AS char] -- (Note: Available in Hive 0.13 and later)
| SERDE serde_name [WITH SERDEPROPERTIES (property_name=property_value, property_name=property_value, ...)]
实例;
数据格式：
192.168.57.4 - - [29/Feb/2016:18:14:35 +0800] “GET /bg-upper.png HTTP/1.1” 304 -
192.168.57.4 - - [29/Feb/2016:18:14:35 +0800] “GET /bg-nav.png HTTP/1.1” 304 -
192.168.57.4 - - [29/Feb/2016:18:14:35 +0800] “GET /asf-logo.png HTTP/1.1” 304 -
192.168.57.4 - - [29/Feb/2016:18:14:35 +0800] “GET /bg-button.png HTTP/1.1” 304 -
192.168.57.4 - - [29/Feb/2016:18:14:35 +0800] “GET /bg-middle.png HTTP/1.1” 304 -
192.168.57.4 - - [29/Feb/2016:18:14:36 +0800] “GET / HTTP/1.1” 200 11217
192.168.57.4 - - [29/Feb/2016:18:14:36 +0800] “GET / HTTP/1.1” 200 11217
SQL语句：
CREATE TABLE logtbl (
host STRING,
identity STRING,
t_user STRING,
time STRING,
request STRING,
referer STRING,
agent STRING)
ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.RegexSerDe'
WITH SERDEPROPERTIES (
"input.regex" = "([^ ]*) ([^ ]*) ([^ ]*) \\[(.*)\\] \"(.*)\" (-|[0-9]*) (-|[0-9]*)"
)
STORED AS TEXTFILE;
