SHIFTLEFT

shiftleft(value, n)

Description

Performs a left bitwise shift on an integer value. Shifting left by n bits is equivalent to multiplying by 2n. This function supports both int and bigint types.

Parameters

• value: int or bigint type, the value to be shifted
• n: int type, the number of bits to shift, must be greater than or equal to 0

Returns

• Same type as value (int or bigint)
• Returns the result after the left shift
• If value or n is NULL, returns NULL

Examples

SELECT shiftleft(1, 2);
-- Result: 4

SELECT shiftleft(8, 2);
-- Result: 32

SELECT shiftleft(0, 2);
-- Result: 0

SELECT shiftleft(1L, 2);
-- Result: 4

SELECT shiftleft(8L, 2);
-- Result: 32

SELECT shiftleft(NULL, 2);
-- Result: NULL

SELECT shiftleft(1, NULL);
-- Result: NULL

SELECT shiftleft(-4, 2);
-- Result: -16

SELECT shiftleft(1, 10);  -- 210 = 1024
-- Result: 1024

Notes

• Shifting left by n bits is equivalent to multiplying by 2n
• For positive numbers: shiftleft(x, n) = x * 2n
• For negative numbers, the left shift preserves the sign bit.
• The shift operation may cause overflow:
  • int type range: -2,147,483,648 to 2,147,483,647
  • bigint type range: -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
• If the shifted result exceeds the type range, overflow occurs (the result is unpredictable).
• Bit shift operations are bitwise operations and have better performance than multiplication.
• Common use cases:
  • Fast computation of powers of 2
  • Bit flags and bitmask operations
  • Data encoding and decoding
• Related functions:
  • shiftright - Arithmetic right shift (preserves the sign bit)
  • shiftrightunsigned - Logical right shift (does not preserve the sign bit)