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SQL
Constraints
PRIMARY KEY, NOT NULL, UNIQUE, CHECK, DEFAULT and FOREIGN KEY.
0
/ 20 solved
All levels
Basic (7)
Intermediate (8)
Advanced (5)
All
To do
Solved
1
Primary key
Basic
2
Required columns
Basic
3
Unique email
Basic
4
Default value
Basic
5
No negative prices
Basic
6
Rating between 1 and 5
Basic
7
Allowed values only
Basic
8
Composite primary key
Intermediate
9
Foreign key
Intermediate
10
Unique across two columns
Intermediate
11
Dates in the right order
Intermediate
12
Default date and flag
Intermediate
13
Salary rules
Intermediate
14
Find the broken rows
Intermediate
15
Which emails are duplicated?
Intermediate
16
Orders with line items
Advanced
17
Self-referencing manager
Advanced
18
Valid Indian mobile numbers
Interview
Advanced
19
Load only valid rows
Advanced
20
Library design
Interview
Advanced