27 Data Types questions from the SQL bank, written for Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd.
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A.an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
B.a point-in-time type that stores an instant in UTC and converts to the session time zone, unlike a plain timestamp that ignores zones
C.an 8-byte signed integer type used when values may exceed the roughly two-billion limit of an ordinary 4-byte integer
D.an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
Answer + AI explanation with Pro
2. Which term means: "an 8-byte signed integer type used when values may exceed the roughly two-billion limit of an ordinary 4-byte integer"?
Junior
A.BIGINT
B.FLOAT
C.TIMESTAMPTZ
D.VARCHAR
Answer + AI explanation with Pro
3. Which statement is correct?
Junior
A.BIGINT — a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
B.BIGINT — an 8-byte signed integer type used when values may exceed the roughly two-billion limit of an ordinary 4-byte integer
C.BIGINT — a fixed-length character type that pads stored strings with trailing spaces up to the declared width
D.BIGINT — a 128-bit universally unique identifier often used as a key that can be generated on the client without coordinating with the database
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4. What is CHAR?
Junior
A.a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
B.a fixed-length character type that pads stored strings with trailing spaces up to the declared width
C.an 8-byte signed integer type used when values may exceed the roughly two-billion limit of an ordinary 4-byte integer
D.an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
Answer + AI explanation with Pro
5. Which term means: "a fixed-length character type that pads stored strings with trailing spaces up to the declared width"?
Junior
A.TIMESTAMPTZ
B.FLOAT
C.CHAR
D.DECIMAL
Answer + AI explanation with Pro
6. Which statement is correct?
Junior
A.CHAR — a fixed-length character type that pads stored strings with trailing spaces up to the declared width
B.CHAR — a type holding the logical values true or false (and possibly unknown via NULL)
C.CHAR — an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
D.CHAR — a variable-length character type that stores only the actual characters supplied, up to a declared maximum length
Answer + AI explanation with Pro
7. What is VARCHAR?
Junior
A.an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
B.a variable-length character type that stores only the actual characters supplied, up to a declared maximum length
C.a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
D.a type holding the logical values true or false (and possibly unknown via NULL)
Answer + AI explanation with Pro
8. Which term means: "a variable-length character type that stores only the actual characters supplied, up to a declared maximum length"?
Junior
A.BIGINT
B.BOOLEAN
C.VARCHAR
D.FLOAT
Answer + AI explanation with Pro
9. Which statement is correct?
Junior
A.VARCHAR — a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
B.VARCHAR — a point-in-time type that stores an instant in UTC and converts to the session time zone, unlike a plain timestamp that ignores zones
C.VARCHAR — a variable-length character type that stores only the actual characters supplied, up to a declared maximum length
D.VARCHAR — an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
Answer + AI explanation with Pro
10. What is DECIMAL?
Mid
A.a type holding the logical values true or false (and possibly unknown via NULL)
B.a variable-length character type that stores only the actual characters supplied, up to a declared maximum length
C.an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
D.a fixed-length character type that pads stored strings with trailing spaces up to the declared width
Answer + AI explanation with Pro
11. Which term means: "an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point"?
Mid
A.CHAR
B.UUID
C.DECIMAL
D.TIMESTAMPTZ
Answer + AI explanation with Pro
12. Which statement is correct?
Mid
A.DECIMAL — an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
B.DECIMAL — a variable-length character type that stores only the actual characters supplied, up to a declared maximum length
C.DECIMAL — an 8-byte signed integer type used when values may exceed the roughly two-billion limit of an ordinary 4-byte integer
D.DECIMAL — a 128-bit universally unique identifier often used as a key that can be generated on the client without coordinating with the database
Answer + AI explanation with Pro
13. What is FLOAT?
Mid
A.a type holding the logical values true or false (and possibly unknown via NULL)
B.a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
C.an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
D.an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
Answer + AI explanation with Pro
14. Which term means: "an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values"?
Mid
A.BOOLEAN
B.UUID
C.FLOAT
D.VARCHAR
Answer + AI explanation with Pro
15. Which statement is correct?
Mid
A.FLOAT — an 8-byte signed integer type used when values may exceed the roughly two-billion limit of an ordinary 4-byte integer
B.FLOAT — an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
C.FLOAT — an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
D.FLOAT — a type holding the logical values true or false (and possibly unknown via NULL)
Answer + AI explanation with Pro
16. What is TIMESTAMPTZ?
Mid
A.an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
B.a point-in-time type that stores an instant in UTC and converts to the session time zone, unlike a plain timestamp that ignores zones
C.a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
D.an 8-byte signed integer type used when values may exceed the roughly two-billion limit of an ordinary 4-byte integer
Answer + AI explanation with Pro
17. Which term means: "a point-in-time type that stores an instant in UTC and converts to the session time zone, unlike a plain timestamp that ignores zones"?
Mid
A.CHAR
B.DECIMAL
C.UUID
D.TIMESTAMPTZ
Answer + AI explanation with Pro
18. Which statement is correct?
Mid
A.TIMESTAMPTZ — a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
B.TIMESTAMPTZ — an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
C.TIMESTAMPTZ — a point-in-time type that stores an instant in UTC and converts to the session time zone, unlike a plain timestamp that ignores zones
D.TIMESTAMPTZ — a fixed-length character type that pads stored strings with trailing spaces up to the declared width
Answer + AI explanation with Pro
19. What is JSONB?
Mid
A.an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
B.an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
C.a 128-bit universally unique identifier often used as a key that can be generated on the client without coordinating with the database
D.a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
Answer + AI explanation with Pro
20. Which term means: "a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting"?
Mid
A.BIGINT
B.DECIMAL
C.FLOAT
D.JSONB
Answer + AI explanation with Pro
21. Which statement is correct?
Mid
A.JSONB — a 128-bit universally unique identifier often used as a key that can be generated on the client without coordinating with the database
B.JSONB — a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
C.JSONB — an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
D.JSONB — a type holding the logical values true or false (and possibly unknown via NULL)
Answer + AI explanation with Pro
22. What is UUID?
Senior
A.a point-in-time type that stores an instant in UTC and converts to the session time zone, unlike a plain timestamp that ignores zones
B.an exact fixed-precision numeric type (also called NUMERIC) preferred for money because it avoids the rounding errors of binary floating point
C.a 128-bit universally unique identifier often used as a key that can be generated on the client without coordinating with the database
D.a type holding the logical values true or false (and possibly unknown via NULL)
Answer + AI explanation with Pro
23. Which term means: "a 128-bit universally unique identifier often used as a key that can be generated on the client without coordinating with the database"?
Senior
A.CHAR
B.DECIMAL
C.BOOLEAN
D.UUID
Answer + AI explanation with Pro
24. Which statement is correct?
Senior
A.UUID — a fixed-length character type that pads stored strings with trailing spaces up to the declared width
B.UUID — a type holding the logical values true or false (and possibly unknown via NULL)
C.UUID — a 128-bit universally unique identifier often used as a key that can be generated on the client without coordinating with the database
D.UUID — a point-in-time type that stores an instant in UTC and converts to the session time zone, unlike a plain timestamp that ignores zones
Answer + AI explanation with Pro
25. What is BOOLEAN?
Junior
A.a point-in-time type that stores an instant in UTC and converts to the session time zone, unlike a plain timestamp that ignores zones
B.a type holding the logical values true or false (and possibly unknown via NULL)
C.an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
D.a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
Answer + AI explanation with Pro
26. Which term means: "a type holding the logical values true or false (and possibly unknown via NULL)"?
Junior
A.DECIMAL
B.FLOAT
C.BOOLEAN
D.JSONB
Answer + AI explanation with Pro
27. Which statement is correct?
Junior
A.BOOLEAN — a Postgres binary-encoded document type that supports indexing and fast key access, trading slightly slower writes versus the plain text JSON type which preserves formatting
B.BOOLEAN — a type holding the logical values true or false (and possibly unknown via NULL)
C.BOOLEAN — a fixed-length character type that pads stored strings with trailing spaces up to the declared width
D.BOOLEAN — an approximate binary floating-point numeric type that can introduce small rounding errors and is unsuitable for exact monetary values
Answer + AI explanation with Pro
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