MySQL Database Multiple Choice Questions on “Operators”.
1. Which operator is used to return value from JSON columns after evaluating the path and unquoting the result?
a) ->
b) ->>
c) <<
d) >>
Answer: b
Clarification: The operator ‘–>>’ is used to return values from JSON columns after evaluating the path and unquoting the result. It is equivalent to the function ‘JSON_UNQUOTE(JSON_EXTRACT())’.
2. The right shift operator is _____________
a) >>
b) <<
c) <
d) >
Answer: a
Clarification: The right shift operator is ‘>>’. It is used to shift the bits of a number towards the right. The left shift operator is ‘<<‘. It is used to shift the bits of a number to the left.
3. Which operator compares sounds?
a) MATCH SOUNDS
b) CHECK SOUNDS
c) SOUNDS LIKE
d) SOUNDS SIMILAR
Answer: c
Clarification: The operator ‘SOUNDS LIKE’ is used to compare the sound. The ‘RLIKE’ is a synonym for ‘REGEXP’, which is a pattern matching using regular expressions. There are a lot of other operators for use.
4. What does RTF refer to?
a) Rich Text Format
b) Right Text Format
c) Rich Text Function
d) Right Text Function
Answer: a
Clarification: RTF (Rich Text Format) is a format developed by Microsoft that is understood by many word processors. MS-Word is one such program. Many others such as ‘OpenOffice’ understand it too.
5. Which function returns an array of row values?
a) fetchrow_array()
b) fetchrow_arrayref()
c) fetch()
d) fetchrow_hashref()
Answer: a
Clarification: The function ‘fetchrow_array()’ returns an array of row values. ‘fetchrow_arrayref()’ returns a reference to an array of row values. ‘fetch()’ is the same as fetchrow_arrayref().
6. Which function returns a reference to hash of row values?
a) fetchrow_array()
b) fetchrow_arrayref()
c) fetch()
d) fetchrow_hashref()
Answer: d
Clarification: The function ‘fetchrow_hashref()’ returns reference to hash of row values. ‘fetchrow_arrayref()’ returns a reference to an array of row values. ‘fetch()’ is the same as fetchrow_arrayref().
7. ‘fetchrow_hashref()’ returns a reference to the hash of row values keyed by what?
a) row name
b) column name
c) table name
d) database name
Answer: b
Clarification: The function ‘fetchrow_hashref()’ returns a reference to the hash of row values, keyed by the column name. The function ‘fetchrow_arrayref()’ returns a reference to an array of row values.
8. The maximum non zero value for FLOAT is ______________
a) 3.402823466E+38
b) 3.402823466E+37
c) 3.402823466E+39
d) 3.402823466E+35
Answer: a
Clarification: In MySQL, each datatype has its own range. Data types give an idea of the kind of values and the ranges that a variable is allowed to store. The maximum non zero value for FLOAT is 3.402823466E+38.