LEFT

Description

Returns the right part of a character string with the specified number of characters. (RIGHT in Transact-SQL).

Sample Source Pattern

Syntax

SQL Server

LEFT ( character_expression , integer_expression )  

Snowflake SQL

Snowflake SQL complete documentation

LEFT ( <expr> , <length_expr> )

JavaScript

Function used to emulate the behavior

function LEFT(string, index){
      if(index < 0){
          throw new RangeError('Invalid INDEX on LEFT function');
      }
      return string.slice( 0, index);
    }
  return LEFT(STR, INDEX);

Examples

SQL Server

Code:

SELECT LEFT('John Smith', 5) AS FIRST_NAME  

Output:

FIRST_NAME|
----------+
John      |

Snowflake SQL

Code:

SELECT RIGHT('John Smith', 5) AS LAST_NAME  

Output:

FIRST_NAME|
----------+
John      |

JavaScript

Code:

CREATE OR REPLACE FUNCTION left_str(str varchar, index float)
  RETURNS string
  LANGUAGE JAVASCRIPT
AS
$$
    function LEFT(string, index){
      if(index < 0){
          throw new RangeError('Invalid INDEX on LEFT function');
      }
      return string.slice( 0, index);
    }
  return LEFT(STR, INDEX);
$$;
SELECT LEFT_STR('John Smith', 5) AS FIRST_NAME;

Output:

FIRST_NAME|
----------+
John      |