Returns the left part of a character string with the specified number of characters.
LEFT ( character_expression , integer_expression )
Is an expression of character or binary data. character_expression can be a constant, variable, or column. character_expression can be of any data type, except text or ntext, that can be implicitly converted to varchar or nvarchar. Otherwise, use the CAST function to explicitly convert character_expression.
Is a positive integer that specifies how many characters of the character_expression will be returned. If index is negative, an error is returned. If index is type bigint and contains a large value, character_expression must be of a large data type such as varchar(max).
Returns the same type as character_expression and always nullable.
SELECT LEFT('abcdefg', 2);