15.00 - SHIFTLEFT - Teradata Database

Teradata Database SQL Functions, Operators, Expressions, and Predicates

Product
Teradata Database
Release Number
15.00
Content Type
Programming Reference
Publication ID
B035-1145-015K
Language
English (United States)
Last Update
2018-09-24

SHIFTLEFT

Purpose  

Returns the expression target_arg shifted by the specified number of bits (num_bits_arg) to the left. The bits in the most significant positions are lost, and the bits in the least significant positions are filled with zeros.

Syntax  

where:

 

Syntax element…

Specifies…

TD_SYSFNLIB

the name of the database where the function is located.

target_arg

a numeric or variable expression.

num_bits_arg

an integer expression indicating the number of bit positions to shift.

ANSI Compliance

This is a Teradata extension to the ANSI SQL:2011 standard.

Description

 

IF...

THEN the function...

num_bits_arg is equal to zero

returns target_arg unchanged.

num_bits_arg is negative

shifts the bits to the right instead of the left.

target_arg and/or num_bits_arg are NULL

returns NULL.

num_bits_arg is larger than the size of target_arg

returns an error.

The scope of the shift operation is bounded by the size of the target_arg expression. Specifying a shift that is outside the range of target_arg results in an SQL error.

Note: When operating against an integer value (BYTEINT, SMALLINT, INTEGER, or BIGINT), shifting a bit into the most significant position will result in the integer becoming negative. This is because all integers in Teradata Database are signed integers.

Argument Types and Rules

SHIFTLEFT is an overloaded scalar function. It is defined with the following parameter data types for the following (target_arg, num_bits_arg) input combinations:

 

target_arg type

num_bits_arg type

BYTEINT

INTEGER

SMALLINT

INTEGER

INTEGER

INTEGER

BIGINT

INTEGER

VARBYTE(n)

INTEGER

The maximum supported size (n) for VARBYTE is 8192 bytes.

All expressions passed to this function must either match these declared data types or can be converted to these types using the implicit data type conversion rules that apply to UDFs.

Note: The UDF implicit type conversion rules are more restrictive than the implicit type conversion rules normally used by Teradata Database. If any argument cannot be converted to one of the declared data types by following UDF implicit conversion rules, it must be explicitly cast. For details, see “Compatible Types” and “Parameter Types in Overloaded Functions” in SQL External Routine Programming.

If any argument cannot be converted to one of the declared data types, an error is returned indicating that no function exists that matches the DML UDF expression submitted.

For more information on overloaded functions, see “Function Name Overloading” in SQL External Routine Programming.

Result Type and Attributes

The result data type depends on the data type of the target_arg input argument that is passed to the function as shown in the following table:

 

IF the data type of target_arg is...

THEN the result type is...

AND the result format is the default format for...

BYTEINT

BYTEINT

BYTEINT

SMALLINT

SMALLINT

SMALLINT

INTEGER

INTEGER

INTEGER

BIGINT

BIGINT

BIGINT

VARBYTE(n)

VARBYTE(n)

VARBYTE(n)

The maximum supported size (n) for VARBYTE is 8192 bytes.

The default title for SHIFTLEFT is: SHIFTLEFT(target_arg, num_bits_arg).

For information on default data type formats, see SQL Data Types and Literals.

Example  

In the following query, the input argument 3 has a data type of BYTEINT and a binary representation of 00000011. When this value is shifted left by two bits, the result in binary is 00001100. This value translates to a BYTEINT value of 12, which is the result returned by the query.

   SELECT SHIFTLEFT(3,2);