Hive基础sql语法(DML)
DML操作(Data Manipulation Language)
参考官方文档: DML文档
- 因update和delete在Hive中一般用不到,本篇文章不做讲解。本文主要介绍Load和insert操作。
1. LOAD(加载数据)
LOAD作用是加载文件到表中(Loading files into tables)
下面是官网上为我们列出的语法:
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)
1.加载数据到表中时,Hive不做任何转换。加载操作只是把数据拷贝或移动操作,即移动数据文件到Hive表相应的位置。
2.加载的目标可以是一个表,也可以是一个分区。如果表是分区的,则必须通过指定所有分区列的值来指定一个表的分区。
- 3.filepath可以是一个文件,也可以是一个目录。不管什么情况下,filepath被认为是一个文件集合。
LOCAL:表示输入文件在本地文件系统(Linux),如果没有加LOCAL,hive则会去HDFS上查找该文件。
OVERWRITE:表示如果表中有数据,则先删除数据,再插入新数据,如果没有这个关键词,则直接附加数据到表中。
PARTITION:如果表中存在分区,可以按照分区进行导入。
# 创建一张员工表hive> create table emp > (empno int, ename string, job string, mgr int, hiredate string, salary double, comm double, deptno int) > ROW FORMAT DELIMITED > FIELDS TERMINATED BY '\t' ;OKTime taken: 0.651 seconds# 把本地文件系统中emp.txt导入表hive> LOAD DATA LOCAL INPATH '/home/hadoop/emp.txt' OVERWRITE INTO TABLE emp; Loading data to table default.empTable default.emp stats: [numFiles=1, numRows=0, totalSize=886, rawDataSize=0]OKTime taken: 1.848 seconds# 查看表数据hive> select * from emp;OK7369 SMITH CLERK 7902 1980-12-17 800.0 NULL 207499 ALLEN SALESMAN 7698 1981-2-20 1600.0 300.0 307521 WARD SALESMAN 7698 1981-2-22 1250.0 500.0 307566 JONES MANAGER 7839 1981-4-2 2975.0 NULL 207654 MARTIN SALESMAN 7698 1981-9-28 1250.0 1400.0 307698 BLAKE MANAGER 7839 1981-5-1 2850.0 NULL 307782 CLARK MANAGER 7839 1981-6-9 2450.0 NULL 107788 SCOTT ANALYST 7566 1987-4-19 3000.0 NULL 207839 KING PRESIDENT NULL 1981-11-17 5000.0 NULL 107844 TURNER SALESMAN 7698 1981-9-8 1500.0 0.0 307876 ADAMS CLERK 7788 1987-5-23 1100.0 NULL 207900 JAMES CLERK 7698 1981-12-3 950.0 NULL 307902 FORD ANALYST 7566 1981-12-3 3000.0 NULL 207934 MILLER CLERK 7782 1982-1-23 1300.0 NULL 10# 不用OVERWRITE关键字hive> LOAD DATA LOCAL INPATH '/home/hadoop/emp.txt' INTO TABLE emp;# 再次查看hive> select * from emp;OK7369 SMITH CLERK 7902 1980-12-17 800.0 NULL 207499 ALLEN SALESMAN 7698 1981-2-20 1600.0 300.0 307521 WARD SALESMAN 7698 1981-2-22 1250.0 500.0 307566 JONES MANAGER 7839 1981-4-2 2975.0 NULL 207654 MARTIN SALESMAN 7698 1981-9-28 1250.0 1400.0 307698 BLAKE MANAGER 7839 1981-5-1 2850.0 NULL 307782 CLARK MANAGER 7839 1981-6-9 2450.0 NULL 107788 SCOTT ANALYST 7566 1987-4-19 3000.0 NULL 207839 KING PRESIDENT NULL 1981-11-17 5000.0 NULL 107844 TURNER SALESMAN 7698 1981-9-8 1500.0 0.0 307876 ADAMS CLERK 7788 1987-5-23 1100.0 NULL 207900 JAMES CLERK 7698 1981-12-3 950.0 NULL 307902 FORD ANALYST 7566 1981-12-3 3000.0 NULL 207934 MILLER CLERK 7782 1982-1-23 1300.0 NULL 107369 SMITH CLERK 7902 1980-12-17 800.0 NULL 207499 ALLEN SALESMAN 7698 1981-2-20 1600.0 300.0 307521 WARD SALESMAN 7698 1981-2-22 1250.0 500.0 307566 JONES MANAGER 7839 1981-4-2 2975.0 NULL 207654 MARTIN SALESMAN 7698 1981-9-28 1250.0 1400.0 307698 BLAKE MANAGER 7839 1981-5-1 2850.0 NULL 307782 CLARK MANAGER 7839 1981-6-9 2450.0 NULL 107788 SCOTT ANALYST 7566 1987-4-19 3000.0 NULL 207839 KING PRESIDENT NULL 1981-11-17 5000.0 NULL 107844 TURNER SALESMAN 7698 1981-9-8 1500.0 0.0 307876 ADAMS CLERK 7788 1987-5-23 1100.0 NULL 207900 JAMES CLERK 7698 1981-12-3 950.0 NULL 307902 FORD ANALYST 7566 1981-12-3 3000.0 NULL 207934 MILLER CLERK 7782 1982-1-23 1300.0 NULL 10Time taken: 0.137 seconds, Fetched: 28 row(s)# 再次OVERWRITE覆盖导入hive> LOAD DATA LOCAL INPATH '/home/hadoop/emp.txt' OVERWRITE INTO TABLE emp; # 发现数据被覆盖了hive> select * from emp;OK7369 SMITH CLERK 7902 1980-12-17 800.0 NULL 207499 ALLEN SALESMAN 7698 1981-2-20 1600.0 300.0 307521 WARD SALESMAN 7698 1981-2-22 1250.0 500.0 307566 JONES MANAGER 7839 1981-4-2 2975.0 NULL 207654 MARTIN SALESMAN 7698 1981-9-28 1250.0 1400.0 307698 BLAKE MANAGER 7839 1981-5-1 2850.0 NULL 307782 CLARK MANAGER 7839 1981-6-9 2450.0 NULL 107788 SCOTT ANALYST 7566 1987-4-19 3000.0 NULL 207839 KING PRESIDENT NULL 1981-11-17 5000.0 NULL 107844 TURNER SALESMAN 7698 1981-9-8 1500.0 0.0 307876 ADAMS CLERK 7788 1987-5-23 1100.0 NULL 207900 JAMES CLERK 7698 1981-12-3 950.0 NULL 307902 FORD ANALYST 7566 1981-12-3 3000.0 NULL 207934 MILLER CLERK 7782 1982-1-23 1300.0 NULL 10Time taken: 0.164 seconds, Fetched: 14 row(s)
2. insert into到表(Inserting data into Hive Tables from queries)
- 下面是官网上为我们列出的语法:
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_statementINSERT 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_statementINSERT 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;
官网又给我们列出一大堆语法,看着就很可怕,但是仔细整理后再来看看你会发现并没有什么,下面对其进行分析:
- 1 标准语法(Standard syntax):INSERT OVERWRITE TABLE tablename1 select_statement1 FROM from_statement; 其实就是一个简单的插入语句。
- 2.可以使用PARTITION 关键字,进行分区插入。
- 3.OVERWRITE是否选择覆盖。
4 使用插入语法会跑mr作业。
5 multiple inserts:代表多行插入。
- 6 dynamic partition inserts:动态分区插入。
注:这里有两种插语法,也就是加上OVERWRITE关键字和不加的区别。
# insert overwritehive> insert overwrite table emp2 select * from emp;Query ID = hadoop_20180624141010_3063d504-ff2f-4003-843f-7dca60f1dd7eTotal jobs = 3Launching Job 1 out of 3...OKTime taken: 19.554 secondshive> select * from emp2;OK7369 SMITH CLERK 7902 1980-12-17 800.0 NULL 207499 ALLEN SALESMAN 7698 1981-2-20 1600.0 300.0 307521 WARD SALESMAN 7698 1981-2-22 1250.0 500.0 307566 JONES MANAGER 7839 1981-4-2 2975.0 NULL 207654 MARTIN SALESMAN 7698 1981-9-28 1250.0 1400.0 307698 BLAKE MANAGER 7839 1981-5-1 2850.0 NULL 307782 CLARK MANAGER 7839 1981-6-9 2450.0 NULL 107788 SCOTT ANALYST 7566 1987-4-19 3000.0 NULL 207839 KING PRESIDENT NULL 1981-11-17 5000.0 NULL 107844 TURNER SALESMAN 7698 1981-9-8 1500.0 0.0 307876 ADAMS CLERK 7788 1987-5-23 1100.0 NULL 207900 JAMES CLERK 7698 1981-12-3 950.0 NULL 307902 FORD ANALYST 7566 1981-12-3 3000.0 NULL 207934 MILLER CLERK 7782 1982-1-23 1300.0 NULL 10Time taken: 0.143 seconds, Fetched: 14 row(s)# insert追加hive> insert into table emp2 select * from emp;Query ID = hadoop_20180624141010_3063d504-ff2f-4003-843f-7dca60f1dd7eTotal jobs = 3...OKTime taken: 18.539 secondshive> select * from emp2;OK7369 SMITH CLERK 7902 1980-12-17 800.0 NULL 207499 ALLEN SALESMAN 7698 1981-2-20 1600.0 300.0 307521 WARD SALESMAN 7698 1981-2-22 1250.0 500.0 307566 JONES MANAGER 7839 1981-4-2 2975.0 NULL 207654 MARTIN SALESMAN 7698 1981-9-28 1250.0 1400.0 307698 BLAKE MANAGER 7839 1981-5-1 2850.0 NULL 307782 CLARK MANAGER 7839 1981-6-9 2450.0 NULL 107788 SCOTT ANALYST 7566 1987-4-19 3000.0 NULL 207839 KING PRESIDENT NULL 1981-11-17 5000.0 NULL 107844 TURNER SALESMAN 7698 1981-9-8 1500.0 0.0 307876 ADAMS CLERK 7788 1987-5-23 1100.0 NULL 207900 JAMES CLERK 7698 1981-12-3 950.0 NULL 307902 FORD ANALYST 7566 1981-12-3 3000.0 NULL 207934 MILLER CLERK 7782 1982-1-23 1300.0 NULL 107369 SMITH CLERK 7902 1980-12-17 800.0 NULL 207499 ALLEN SALESMAN 7698 1981-2-20 1600.0 300.0 307521 WARD SALESMAN 7698 1981-2-22 1250.0 500.0 307566 JONES MANAGER 7839 1981-4-2 2975.0 NULL 207654 MARTIN SALESMAN 7698 1981-9-28 1250.0 1400.0 307698 BLAKE MANAGER 7839 1981-5-1 2850.0 NULL 307782 CLARK MANAGER 7839 1981-6-9 2450.0 NULL 107788 SCOTT ANALYST 7566 1987-4-19 3000.0 NULL 207839 KING PRESIDENT NULL 1981-11-17 5000.0 NULL 107844 TURNER SALESMAN 7698 1981-9-8 1500.0 0.0 307876 ADAMS CLERK 7788 1987-5-23 1100.0 NULL 207900 JAMES CLERK 7698 1981-12-3 950.0 NULL 307902 FORD ANALYST 7566 1981-12-3 3000.0 NULL 207934 MILLER CLERK 7782 1982-1-23 1300.0 NULL 10Time taken: 0.132 seconds, Fetched: 28 row(s)
- Inserting values into tables(手动插入一条或多条记录,会跑mr作业 不常用)
- 官方用法:
INSERT INTO TABLE tablename [PARTITION (partcol1[=val1], partcol2[=val2] ...)] VALUES values_row [, values_row ...]
hive> create table stu( > id int, > name string > ) > ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t';OKTime taken: 0.253 secondshive> insert into table stu values (1,"zhangsan");Query ID = hadoop_20180624141010_3063d504-ff2f-4003-843f-7dca60f1dd7eTotal jobs = 3...OKTime taken: 16.589 secondshive> select * from stu;OK1 zhangsanTime taken: 0.123 seconds, Fetched: 1 row(s)
3. 数据导出(Writing data into the filesystem from queries)
查询结果可以通过语句插入文件系统中:
- 下面是官网上为我们列出的语法:
Standard syntax:(标准语法)INSERT OVERWRITE [LOCAL] DIRECTORY directory1[ROW FORMAT row_format] [STORED AS file_format] (Note: Only available starting with Hive 0.11.0)SELECT ... FROM ...
Hive extension (multiple inserts):(导出多条记录)
FROM from_statement
INSERT OVERWRITE [LOCAL] DIRECTORY directory1 select_statement1
[INSERT OVERWRITE [LOCAL] DIRECTORY directory2 select_statement2] ...
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: Only available starting with Hive 0.13)
**LOCAL**:加上LOCAL关键字代表导入本地系统,不加默认导入HDFS; **STORED AS**:可以指定存储格式。```shellhive> insert overwrite local directory '/home/hadoop/stu' ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' select * from stu;Query ID = hadoop_20180624153131_97271014-abcf-4e70-b318-7de85d27c97fTotal jobs = 1...OKTime taken: 15.09 seconds# 结果[hadoop@hadoop000 stu]$ pwd/home/hadoop/stu[hadoop@hadoop000 stu]$ cat 000000_0 1 zhangsan# 导出多条记录hive> from emp > INSERT OVERWRITE LOCAL DIRECTORY '/home/hadoop/tmp/hivetmp1' > ROW FORMAT DELIMITED FIELDS TERMINATED BY "\t" > select empno, ename > INSERT OVERWRITE LOCAL DIRECTORY '/home/hadoop/tmp/hivetmp2' > ROW FORMAT DELIMITED FIELDS TERMINATED BY "\t" > select ename;Query ID = hadoop_20180624153131_97271014-abcf-4e70-b318-7de85d27c97fTotal jobs = 1...OKTime taken: 16.261 seconds# 结果[hadoop@hadoop000 tmp]$ cd hivetmp1[hadoop@hadoop000 hivetmp1]$ lltotal 4-rw-r--r-- 1 hadoop hadoop 154 Jun 24 15:39 000000_0[hadoop@hadoop000 hivetmp1]$ cat 000000_0 7369 SMITH7499 ALLEN7521 WARD7566 JONES7654 MARTIN7698 BLAKE7782 CLARK7788 SCOTT7839 KING7844 TURNER7876 ADAMS7900 JAMES7902 FORD7934 MILLER[hadoop@hadoop000 hivetmp1]$ cd ..[hadoop@hadoop000 tmp]$ cd hivetmp2[hadoop@hadoop000 hivetmp2]$ cat 000000_0 SMITHALLENWARDJONESMARTINBLAKECLARKSCOTTKINGTURNERADAMSJAMESFORDMILLER
参考: https://blog.csdn.net/yu0_zhang0/article/details/79007784