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This chapter explains the built-in operators of Hive. There are four types of 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. |
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