How do I use a CASE Statement in Hive?

First, it will check for “fail” or “detained” in the status of each dept and course grouped together. If it finds “fail” or “detained”, it will output “fail” as the status . Else, if an “absent” is found in the same group, it will output “absent” as the status .

Does Hive support CASE Statement?

Hive supports Case statements to check the conditions against the column values. If any of the condition is true, it will stop to check the other conditions and returns the value that specified in THEN clause. In case none of the condition is met, it will return the value in the ELSE clause.

What type of Hive function allows for IF statements?

If condition/statement in Hive. Hive supports many conditional functions such as If, isnull, isnotnull, nvl, nullif, COALESCE and CASE. The If condition is used to validate the condition on the column values. In the if condition, we need to mention the true/false values to be returned.

What is NVL function in Hive?

Use nvl() function in Hive to replace all NULL values of a column with a default value, In this article, I will explain with an example. You can use this function to. Replace all NULL values with -1 or 0 or any number for the integer column. Replace all NULL values with empty space for string types.

What is Concat_ws in Hive?

CONCAT_WS() stands for Concatenate With Separator and is a special form of CONCAT() . The first argument is the separator for the rest of the arguments. The separator is added between the strings to be concatenated. The separator can be a string, as can the rest of the arguments.

What is Rlike in Hive?

RLIKE (Right-Like) is a special function in Hive where if any substring of A matches with B then it evaluates to true. It also obeys Java regular expression pattern. Users don’t need to put % symbol for a simple match in RLIKE.

What is Hive query language?

Hive Query Language (HiveQL) is a query language in Apache Hive for processing and analyzing structured data. It separates users from the complexity of Map Reduce programming. It reuses common concepts from relational databases, such as tables, rows, columns, and schema, to ease learning.

What is decode in Hive?

decode(, ,, …< search N>, , ) Compares an expression to one or more possible values, and returns a corresponding result when a match is found.

IS NULL condition in Hive?

When you define a table in Hive with a partitioning column of type STRING, all NULL values within the partitioning column appear as __HIVE_DEFAULT_PARTITION__ in the output of a SELECT from Hive statement. This difference in output only occurs when the partitioning column is a STRING value.

What is Regexp_replace in Hive?

Hive REGEXP_REPLACE Function Searches a string for a regular expression pattern and replaces every occurrence of the pattern with the specified replacement.

What is Regexp_replace in hive?

What is Collect_list in hive?

From https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF I found the below, but want some more details: collect_list(col) Returns a list of objects with duplicates. Reply.

https://www.youtube.com/watch?v=9koJYPwsw40