LEFT JOIN

Issue:
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This problem occurs when DATE (or related) column / value
is compared to a string in the format 'YYYYMMDD'. When a
DATETIME column is involved, values shouldn't be compared
as strings since it won't take the format into account.

Similar problems were found in CASE and IN statements.

Solution:
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If DATE (or related) values are involved, use
"cmp_item_datetime" for comparision. This will take the
relevant format into account.

To handle TIME values "cmp_item_datetime" has a new flag
to call "get_time_value" for that case. Also making
warn_item into a const to make sure the object isn't
modified.