Problem with oversized sql IN() clause (Bug #1308792)

Currently institution data daily cronjob fails if the number of items
wanted to be prepared for the IN() clause exceeds 46,000. This causes
adodb to hit memory limit and fail out.

Have taken the three sql commands from various places that make up the
call and made them nested to avoid overly long prepared statement.

Change-Id: I5e38c01194f7b2c3f3899c1573a69411ac273c18
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>