templates: how to create WHERE string for multiple primary keys

[fho]

Hello,

I wonder what the intended way is to build a WHERE statements to match all primary key in a template like:
WHERE id1 = $1 AND id2 = $2 AND id3 = $3.
With intended I means, without using legacy or custom functions.

The only way I found is really ugly:

sqlstr + = " WHERE"
{{ range $i, $field := $t.PrimaryKeys -}}
       // Sprintf code is generated because of a missing arith. add template function
	sqlstr+= " {{ $field.SQLName }} =  $" + fmt.Sprint(i - 1)
       // if statement code is generated because comparision can not be done in template, because of missing add function
	if {{ $i }} + 1 != {{ (len $t.PrimaryKeys) }} {
		sqlstr += " AND"
	}
{{ end -}}

I could define add, sub functions in funcs.go.tpl to improve it.
This seems such a basic scenario though that I think that I'm probably missing the simple intended way to do it? :-)

thanks