format() function with string_agg

[Raj Gandhi <raj01gandhi@xxxxxxxxx>]

I'm trying to use format() function with string_agg with Postgres 9.1.9 but getting error - "too few arguments for format"

I have two tables t_message and t_message_args. Table t_message   has 'message' column with text in the format 'Test message first arg is %1$s and second arg  %2$s end-of-message'

              id             | integer           |

              message | character varying |

And the second table t_message_args contains message argument and values 

              id           | integer           |

             arg          | integer           |

             argvalue  | character varying |

Here is the SQL that uses format() function to retrieve formatted message by replacing arg value in the message:

=

select m.id, format(m.message, string_agg(a.argvalue, ',' order by a.arg)

from t_message m, t_message_args a

where m.id = a.id

group by m.id, m.message

ERROR:  too few arguments for format

********** Error **********

ERROR: too few arguments for format

SQL state: 22023