CREATE FUNCTION [dbo].[num_rows_in_A_fn] ()
RETURNS int
BEGIN
     DECLARE @num_rows int 
    SET @num_rows = (select COUNT(*) from A)
	
	if @num_rows = 0
		begin
		WAITFOR DELAY '00:00:10';		
                -- call itself
                exec [dbo].[num_rows_in_A_fn]	
                end			
    RETURN @num_rows
 END

EXEC msdb..sp_start_job @job_name= 'jobname here'

CREATE FUNCTION [dbo].[num_rows_in_A_fn] ()
RETURNS int
BEGIN
     DECLARE @num_rows int 
    SET @num_rows = (select COUNT(*) from A)
	
	if @num_rows = 0
		begin
		WAITFOR DELAY '00:00:10';		
                -- call itself
                exec [dbo].[num_rows_in_A_fn]	
                end			
    RETURN @num_rows
 END

CREATE PROCEDURE [dbo].[RunJob] AS
BEGIN
SET NOCOUNT ON;     
DECLARE @num_rows int;
SET @num_Rows = 999;

WHILE @num_rows > 0
BEGIN
    SET @num_rows = (select COUNT(*) from A);
	
    if @num_rows > 0
        WAITFOR DELAY '00:00:10';		

    -- Possibly add some code to prevent an infinite loop?
END

-- Call job:
exec [dbo].[TheJobYouWantToRun]	

END