SQL Server 2012 :: Combining Master And Detail Records In New Table

CREATE TABLE DHS(CUSTOMERNBR VARCHAR(20), CONTRACT VARCHAR(20), SUBCONTRACT VARCHAR(20) , STARTDATE DATETIME, ENDDATE DATETIME, EFLAG VARCHAR(20), HFLAG VARCHAR(20))

The data which will be going into this table is from two table which have a 1 to many relationship:

Here is the 1 side and data:

CREATE TABLE CUSTOMERS(
CUSTOMERNBR VARCHAR(20),
CONTRACT VARCHAR(20),
SUBCONTRACT VARCHAR(20),
STARTDATE DATETIME,
ENDDATE DATETIME DEFAULT '12/31/2099')

[Code] ....

Here is the Many side and data:

CREATE TABLE FLAGS(CUSTOMERNBR VARCHAR(20), FLAGCODE VARCHAR(20), STARTDATE DATETIME, ENDDATE DATETIME DEFAULT '12/31/2099')
INSERT INTO FLAGS(CUSTOMERNBR, FLAGCODE, STARTDATE, ENDDATE) VALUES('10001000101', 'H', '02/01/2014', '03/31/2014')

[Code] ....

The CUSTOMERS table holds the record date span into which the FLAGS table records have to "fit". In no case will the date spans from the FLAGS table fall outside the STARTDATE - ENDDATE span in the CUSTOMERS table for any CUSTOMERNBR. Here is an example of the final expected output in the DHS table from combining records in the CUSTOMERS and FLAGS tables:

CUSTOMERNBRCONTRACTSUBCONTRACTSTARTDATEENDDATEEFLAGHFLAG
10001000101A910400801/01/201401/31/2014
10001000101A910400802/01/201403/21/2014H
10001000101A910400804/01/201404/30/2014
10001000101A910400805/01/201405/31/2014H
10001000101A910400806/01/201412/31/2099E
10001000102A555500101/01/201403/31/2014E
10001000102A555500104/01/201404/30/2014EH
10001000102A555500105/01/201406/30/2014E
10001000102A555500107/01/201412/31/2099
10001000103A666600401/01/201410/01/2014