How to calculate the manpower distribution??

Try this as an option (Can't up load because of firewalls and world domination is likely to occur by having excel files uploaded apparently!!!)

In G1 type a date
then below than type the following formulas. When you type them in enter them with Cntl + Shift + Enter as they are array formulas and you will know they are right because they will also have a squiggly bracket around them {}

In G2 =SUM(IF(G1>=$A$2:$A$471,1,0)*IF(G1<=$B$2:$B$471,1,0)*$C$2:$C$471) for plumbers
In G3 =SUM(IF(G1>=$A$2:$A$471,1,0)*IF(G1<=$B$2:$B$471,1,0)*$D$2:$D$471) for electricians
in G4 =SUM(IF(G1>=$A$2:$A$471,1,0)*IF(G1<=$B$2:$B$471,1,0)*$E$2:$E$471) for AC techs

You can then simply change the date in G1 Or you can drag across the screen to fill multiple dates and drag the below formulas across too if you want to look at say a month at a time

For total demand by trade by day,

Row\Col	A	B	C	D	E	F	G	H	I	J	K	L
1								12146	12929	9920		H1 and across: =SUM(H3:H472)
2	Start	Finish	Plumber	Electrician	AC Tech		Date	Plumber	Electrician	AC Tech
3	24-Jul	25-Jul	3				06-Jul	10	0	0		G3: =MIN($A$3:$B$472)
4	02-Aug	06-Aug	3				07-Jul	68	140	30		G4 and down: =G3+1
5	27-Jul	30-Jul	6				08-Jul	78	176	65		H3 and across & down: =SUMIFS(C$3:C$472, $A$3:$A$472, "<=" & $G3, $B$3:$B$472, ">=" & $G3)
6	01-Aug	02-Aug	3				09-Jul	96	164	65
7	04-Aug	05-Aug	5				10-Jul	59	124	65
8	27-Jul	30-Jul	5				11-Jul	86	176	80
9	01-Aug	02-Aug	4				12-Jul	86	184	119
10	25-Jul	30-Jul	5				13-Jul	86	192	129
11	01-Aug	02-Aug	4				14-Jul	78	208	129
12	02-Aug	30-Aug		10			15-Jul	142	268	129
13	06-Aug	08-Aug		3			16-Jul	131	248	91
14	03-Aug	03-Aug		4			17-Jul	125	232	91
15	04-Aug	06-Aug		4			18-Jul	170	236	93
16	29-Aug	01-Sep		4			19-Jul	225	228	92
17	07-Sep	07-Sep		4			20-Jul	256	296	152
18	01-Aug	02-Aug		4			21-Jul	251	292	130
19	18-Aug	20-Aug		4			22-Jul	265	256	130
20	01-Sep	10-Sep		12			23-Jul	260	272	130
21	10-Aug	10-Sep	6		5		24-Jul	276	252	130
22	08-Jul	14-Jul	15				25-Jul	300	408	160
23	11-Jul	15-Jul	1				26-Jul	274	392	160
24	19-Aug	29-Aug	4				27-Jul	309	368	160
25	27-Jul	29-Jul	12				28-Jul	299	356	160
26	30-Jul	30-Jul	2				29-Jul	297	444	195
27	25-Aug	01-Sep	10				30-Jul	285	456	195
28	07-Jul	09-Jul		16			31-Jul	155	160	160
29	19-Jul	22-Jul		8			01-Aug	208	362	160
30	10-Jul	13-Jul	1				02-Aug	174	340	160