To sum a table if a cell contains numbers

[Exkast]

Hi everyone, great forum!
Here´s my question:

I have a table called "table". Two columns in the table, named "date" and "amount".

In the "date" column, I have a date that is formatted like this YYYYMMDD

My table looks like this:

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I am trying to write a formula that sums the correspondent cells in column "amount", when "date" contains "200905" (in the table example above, the sum I´m after would be 300).

These are the formulas I´m not getting to work:

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I´ve also tried with wild cards, such as:

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I´ve also tried to change the format of the date-column to text and numbers, with no improvement. Any suggestions??
Thanks!

*edit*
If I have text in the "date" column instead of numbers, the first formula above works. For instance, if the table is:

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Then the formula

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would return 300

[martindwilson]

=sumproduct((month($a$1:$a$100)=5)*(year($a$1:$a$100)=2009)*$b$1:$b$100)

[Exkast]

This works if column "date" is formatted as date, thanks!

Could I get it to work if the column "date" is formatted as "general" (no specific format)?

[martindwilson]

yep try
=SUMPRODUCT(--(LEFT(A1:A100,4)="2009"),--(MID($A$1:$A$100,5,2)="05"),$B$1:$B$100)