How do I turn off the substitution variable in hive?
Disabling Variable Substitution By default Hive substitutes all variables, you can disable these using (hive. variable. substitute=true) in case if you wanted to run a script without substitution variables.
How do I pass a variable in hive?
Hive command to pass the value to the variable and execute the queries. Here we are passing the value “Banking_Db” to the variable database using the –hivevar option and -f is used the execute the hive queries that are present inside the file.
How do you store Hive query results in a variable?
Bookmark this question. Show activity on this post. ./hive -e “use telecom;insert overwrite local directory ‘/tmp/result’ select avg(a) from abc;” ./hive –hiveconf MY_VAR =`cat /tmp/result/000000_0`;
Can we declare variables in hive?
It is possible. Please find the below code to create a variable in Hive. hive> SET cust_id = 1234567890; Once you create variable you can use it in your query like below.
What is the difference between Hivevar and Hiveconf?
No difference except the namespace. hiveconf and hivevar are different namespaces. hivevar namespace was added just to separate configuration properties namespace and Hive variables namespace.
What is Hive auto convert join?
hive.auto.convert.join When this parameter set to true , Hive will automatically check if the smaller table file size is bigger than the value specified by hive. mapjoin. smalltable. filesize , if it’s larger than this value then query execute through common join.
What is hive auto convert join?
How do I run a Hive query in shell script?
Now, let us see how to write the scripts in Hive and run them in CDH4:
- Step 1: Writing a Hive script. To write the Hive Script the file should be saved with . sql extension.
- Step 2: Running the Hive Script. The following is the command to run the Hive script: Command: hive –f /home/cloudera/sample.sql.
How do I concatenate strings in hive?
The string functions in Hive are listed below:
- ASCII( string str )
- CONCAT( string str1, string str2… )
- CONCAT_WS( string delimiter, string str1, string str2… )
- FIND_IN_SET( string search_string, string source_string_list )
- LENGTH( string str )
- LOWER( string str ), LCASE( string str )
Which join is faster in Hive?
If both tables have the same amount of buckets and the data is sorted by the bucket keys, Hive can perform the faster Sort-Merge Join.
Which Hive join is very fast?
Map join. Map join is used when one of the join tables is small enough to fit in the memory, so it is very fast but limited. Hive can convert map join automatically with the following settings.
How do you automate a hive query?
we call the scripting in hive as hive query lanquage. you can run hive scripts from command line hive -e ‘command’ or hive -f /pathtohql’. Finally use a cronjob or oozie coordinator job to schedule it .
What is CLI in hive?
Hive CLI is a legacy tool which had two main use cases. The first is that it served as a thick client for SQL on Hadoop and the second is that it served as a command line tool for Hive Server (the original Hive server, now often referred to as “HiveServer1”).
How do I concatenate two fields in Hive?
Use concat_ws function to concatenate values with ^ as a delimiter. If columns are not string, wrap them with cast as string using shell, this will allow concat_ws work with strings and not-string columns.
Can Hive replace Rdbms?
No. It cannot replace general “relational databases”.