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Big Data - Hive

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Lesson Description


Lession - #1140 Hive Built-in Operators

There are four types of Built-in operators in Hive:

  • Relational Operators
  • Arithmetic Operators
  • Logical Operators
  • Complex Operators
Relational Operators
These operators are used to compare two operands. The following table describes the relational operators available in Hive:
Operator Operand Description
A = B all primitive types TRUE if expression A is equivalent to expression B otherwise FALSE.
A != B all primitive types TRUE if expression A is not equivalent to expression B otherwise FALSE.
A < B all primitive types TRUE if expression A is less than expression B otherwise FALSE.
A <= B all primitive types TRUE if expression A is less than or equal to expression B otherwise FALSE.
A > B all primitive types TRUE if expression A is greater than expression B otherwise FALSE.
A >= B all primitive types TRUE if expression A is greater than or equal to expression B otherwise FALSE.
A IS NULL all types TRUE if expression A evaluates to NULL otherwise FALSE.
A IS NOT NULL all types FALSE if expression A evaluates to NULL otherwise TRUE.
A LIKE B Strings TRUE if string pattern A matches to B otherwise FALSE.
A RLIKE B Strings NULL if A or B is NULL, TRUE if any substring of A matches the Java regular expression B , otherwise FALSE.
A REGEXP B Strings Same as RLIKE.
Example
Let us assume the employee table is composed of fields named Id, Name, Salary, Designation, and Dept as shown below. Generate a query to retrieve the employee details whose Id is 1205. 

+-----+--------------+--------+---------------------------+------+
| Id  | Name         | Salary | Designation               | Dept |
+-----+--------------+------------------------------------+------+
|1201 | Gopal        | 45000  | Technical manager         | TP   |
|1202 | Manisha      | 45000  | Proofreader               | PR   |
|1203 | Masthanvali  | 40000  | Technical writer          | TP   |
|1204 | Krian        | 40000  | Hr Admin                  | HR   |
|1205 | Kranthi      | 30000  | Op Admin                  | Admin|
+-----+--------------+--------+---------------------------+------+
The following query is executed to retrieve the employee details using the above table: 

hive> SELECT * FROM employee WHERE Id=1205;
On successful execution of query, you get to see the following response: 

+-----+-----------+-----------+----------------------------------+
| ID  | Name      | Salary    | Designation              | Dept  |
+-----+---------------+-------+----------------------------------+
|1205 | Kranthi   | 30000     | Op Admin                 | Admin |
+-----+-----------+-----------+----------------------------------+
The following query is executed to retrieve the employee details whose salary is more than or equal to Rs 40000. 

hive> SELECT * FROM employee WHERE Salary>=40000;
On successful execution of query, you get to see the following response: 

+-----+------------+--------+----------------------------+------+
| ID  | Name       | Salary | Designation                | Dept |
+-----+------------+--------+----------------------------+------+
|1201 | Gopal      | 45000  | Technical manager          | TP   |
|1202 | Manisha    | 45000  | Proofreader                | PR   |
|1203 | Masthanvali| 40000  | Technical writer           | TP   |
|1204 | Krian      | 40000  | Hr Admin                   | HR   |
+-----+------------+--------+----------------------------+------+
Arithmetic Operators
These operators support various common arithmetic operations on the operands. All of them return number types. The following table describes the arithmetic operators available in Hive:
Operators Operand Description
A + B all number types Gives the result of adding A and B.
A - B all number types Gives the result of subtracting B from A.
A * B all number types Gives the result of multiplying A and B.
A / B all number types Gives the result of dividing B from A.
A % B all number types Gives the reminder resulting from dividing A by B.
A & B all number types Gives the result of bitwise AND of A and B.
A | B all number types Gives the result of bitwise OR of A and B.
A ^ B all number types Gives the result of bitwise XOR of A and B.
~A all number types Gives the result of bitwise NOT of A.
Example
The following query adds two numbers, 20 and 30. 

hive> SELECT 20+30 ADD FROM temp;
On successful execution of the query, you get to see the following response: 

+--------+
|   ADD  |
+--------+
|   50   |
+--------+
Logical Operators
The operators are logical expressions. All of them return either TRUE or FALSE.
Operators Operands Description
A AND B boolean TRUE if both A and B are TRUE, otherwise FALSE.
A && B boolean Same as A AND B.
A OR B boolean TRUE if either A or B or both are TRUE, otherwise FALSE.
A || B boolean Same as A OR B.
NOT A boolean TRUE if A is FALSE, otherwise FALSE.
!A boolean Same as NOT A.
Example
The following query is used to retrieve employee details whose Department is TP and Salary is more than Rs 40000. 

hive> SELECT * FROM employee WHERE Salary>40000 && Dept=TP;
On successful execution of the query, you get to see the following response: 

+------+--------------+-------------+-------------------+--------+
| ID   | Name         | Salary      | Designation       | Dept   |
+------+--------------+-------------+-------------------+--------+
|1201  | Gopal        | 45000       | Technical manager | TP     |
+------+--------------+-------------+-------------------+--------+
Complex Operators
These operators provide an expression to access the elements of Complex Types.
Operator Operand Description
A[n] A is an Array and n is an int It returns the nth element in the array A. The first element has index 0.
M[key] M is a Map<K, V> and key has type K It returns the value corresponding to the key in the map.
S.x S is a struct It returns the x field of S.

Hive Partitioning Hive Built-in Functions