What this SQL statement is doing?

Hi ABAPers,

Can somebody help me in understanding what the below SQL statement is doing..

  SELECT * FROM /BIC/ADSO00 AS tb1

      INNER JOIN /BIC/PMASTER as tbl2

      ON tbl1~field1 = tbl2~field1

      AND tbl12~field2 = tbl2~field2

      INTO CORRESPONDING FIELDS OF TABLE gt_itab

      FOR ALL ENTRIES IN SOURCE_PACKAGE

      WHERE tbl1~field3 = SOURCE_PACKAGE-field3

      AND tbl1~field4 BETWEEN lv_minper AND lv_maxper

      AND tbl1~field5 = SOURCE_PACKAGE-field5

      AND tbl1~field6 = '0100'

      AND tbl2~OBJVERS = 'A'.

thanks in advance !!

Bharath S