Impala SHOW Statement – Listing the Tables using Hue
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In our last Impala tutorial, we learned to create table statements, drop table statements in Impala. in this tutorial, we will discuss Impala Show Statements, is used to get information about different types of Impala objects. Moreover, we will discuss, how to get information with Impala SHOW Statement. Also, we will cover its syntax, usage as well as an example to understand it well.
So, let’s start Impala Show Statements.
2. How to use Impala SHOW Statement?
Basically, to get information about different types of Impala objects we use the Impala SHOW statement. In addition, it is a flexible way to do it.
In other words, we can say to get the list of all the existing tables in the current database we use the show tables statement in Impala.
Follow this link to know about Impala Select Statement
a. Syntax of Show Statements in Impala
So, the syntax for using Impala SHOW Statement is-
SHOW DATABASES [[LIKE] 'pattern'] SHOW SCHEMAS [[LIKE] 'pattern'] - an alias for SHOW DATABASES SHOW TABLES [IN database_name] [[LIKE] 'pattern'] SHOW [AGGREGATE | ANALYTIC] FUNCTIONS [IN database_name] [[LIKE] 'pattern'] SHOW CREATE TABLE [database_name].table_name SHOW TABLE STATS [database_name.]table_name SHOW COLUMN STATS [database_name.]table_name SHOW PARTITIONS [database_name.]table_name SHOW FILES IN [database_name.]table_name [PARTITION (key_col=value [, key_col=value]] SHOW ROLES SHOW CURRENT ROLES SHOW ROLE GRANT GROUP group_name SHOW GRANT ROLE role_name
Also, to see the appropriate objects in the current database, issue a SHOW object_type statement, or to see objects in a specific database SHOW object_type IN database_name.
Moreover, using Unix-style * wildcards and allowing | for alternation, the optional pattern argument is a quoted string literal. Also, the preceding LIKE keyword is optional. Although, make sure use all lowercase letters in the pattern string because all object names are stored in lowercase.
show databases 'a*'; show databases like 'a*'; show tables in some_db like '*fact*'; use some_db; show tables '*dim*|*fact*';
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3. Example of SHOW Statements in Impala
Let us understand it with an example of the show tables statement. So, begin with changing the context to the required database if we want to get the list of tables in a particular database. Then using show tables statement we will get the list of tables in it.
[quickstart.cloudera:21000] > use my_db; Query: use my_db [quickstart.cloudera:21000] > show tables;
Moreover, Impala fetches the list of all the tables in the specified database, on executing the above query.
Query: show tables +-----------+ | name | +-----------+ | customers | | employee | +-----------+ Fetched 2 row(s) in 0.10s
4. Listing the Tables using Hue
There are several steps you have to follow while Listing the Tables using Hue, such as:
- At first, select the context as my_db. Further, type the show tables statement in Impala Query editor then click on the execute button.
- Afterward, we can see the list of the tables if we scroll down and select the results tab just after executing the query.
So, this was all in the Impala SHOW Statements. Hope you like our explanation.