Table:
0
A
B
C
D
E
F
G
H
1
document id
document status code
document type code
shipping agent code
receipt date
receipt number
other details
documents
2
1
working
CD
UP
2008-04-21 20:42:25
19
z
3
2
done
Paper
US
1974-05-08 00:00:46
34
h
4
3
done
Paper
UP
2014-12-25 17:22:44
93
h
5
4
done
Paper
US
1973-11-05 21:48:53
80
q
6
7
working
CD
SH
1982-09-27 14:52:15
61
w
7
10
overdue
Paper
UP
1976-09-15 19:24:17
8
m
8
12
overdue
Hard Drive
US
1996-05-31 06:51:58
69
n
9
13
working
CD
UP
2015-04-03 09:36:19
79
y
10
14
working
CD
FE
2017-07-02 17:39:09
117
u
11
15
overdue
CD
UP
1986-12-14 14:18:59
37
r
12
17
done
Paper
FE
1983-09-26 09:32:56
55
p
13
20
working
Paper
UP
1996-07-27 03:30:40
189
x
14
23
working
Hard Drive
FE
1999-04-17 14:19:32
124
b
15
24
working
Hard Drive
FE
2005-09-30 00:10:02
114
j
16
25
overdue
Hard Drive
AL
1985-11-05 17:59:34
83
u

Questions and formulas:
Question: All documents ids and receipt dates
Formula: UNIQUE(HSTACK(A1,E1))
Formula2: UNIQUE(HSTACK(A2:A16,E2:E16))
Level: easy
Question: How many documents have been completed? 
Formula: ROWS(UNIQUE(FILTER(H1, B1="done")))
Formula2: ROWS(UNIQUE(FILTER(H2:H16, B2:B16="done")))
Level: medium
Question: the type code and document information of No.2 document.
Formula: LET(query1,FILTER(A1:H1,A1=2),UNIQUE(CHOOSECOLS(query1,3,8)))
Formula2: LET(query1,FILTER(A2:H16,A2:A16=2),UNIQUE(CHOOSECOLS(query1,3,8)))
Level: hard
Question: What are ids and documents information of done papers?
Formula: LET(query1,FILTER(A1:H1,(B1="done")*(C1="paper")),UNIQUE(CHOOSECOLS(query1,1,8)))
Formula2: LET(query1,FILTER(A2:H16,(B2:B16="done")*(C2:C16="paper")),UNIQUE(CHOOSECOLS(query1,1,8)))
Level: hard
Question: the receipt date and documents information of the third document
Formula: LET(query1,FILTER(A1:H1,A1=3),UNIQUE(CHOOSECOLS(query1,5,8)))
Formula2: LET(query1,FILTER(A2:H16,A2:A16=3),UNIQUE(CHOOSECOLS(query1,5,8)))
Level: hard
Question: The ids and receipt dates of documents
Formula: UNIQUE(HSTACK(A1,E1,H1))
Formula2: UNIQUE(HSTACK(A2:A16,E2:E16,H2:H16))
Level: easy
Question: How many documents are done?
Formula: ROWS(UNIQUE(FILTER(H1, B1="done")))
Formula2: ROWS(UNIQUE(FILTER(H2:H16, B2:B16="done")))
Level: medium
Question: the receipt date and document information of No.3 document.
Formula: LET(query1,FILTER(A1:H1,A1=3),UNIQUE(CHOOSECOLS(query1,5,8)))
Formula2: LET(query1,FILTER(A2:H16,A2:A16=3),UNIQUE(CHOOSECOLS(query1,5,8)))
Level: hard