Conversion functions:

1. TO_DATE: It will convert the given date into oracle standard date format

D		:Day of week (1-7).
DAY		:Name of day.
DD		:Day of month (1-31)
DDD		:Day of year (1-366)
YEAR	:Year, spelled out
YYYY	:4-digit year
YYY		:Last 3 digit(s) of year.
YY		:Last 2 digit(s) of year.
Y		:Last 1 digit(s) of year.
MM		:Month (01-12; JAN = 01).
MON		:Abbreviated name of month.
MONTH	:Name of month, padded with blanks to length of 9 characters.
D		:Day of week (1-7).
DAY		:Name of day.
DD		:Day of month (1-31).
DDD		:Day of year (1-366).
DY		:Abbreviated name of day.
HH		:Hour of day (1-12).
HH12	:Hour of day (1-12).
HH24	:Hour of day (0-23).
MI		:Minute (0-59).
SS		:Second (0-59).
SSSSS	:Seconds past midnight (0-86399)
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2. TO_CHAR: It is used to convert the given date in to string format

D		:Day of week (1-7).
DAY		:Name of day.
DD		:Day of month (1-31)
DDD		:Day of year (1-366)
YEAR	:Year, spelled out
YYYY	:4-digit year
YYY		:Last 3 digit(s) of year.
YY		:Last 2 digit(s) of year.
Y		:Last 1 digit(s) of year.
MM		:Month (01-12; JAN = 01).
MON		:Abbreviated name of month.
MONTH	:Name of month, padded with blanks to length of 9 characters.
D		:Day of week (1-7).
DAY		:Name of day.
DD		:Day of month (1-31).
DDD		:Day of year (1-366).
DY		:Abbreviated name of day.
HH		:Hour of day (1-12).
HH12	:Hour of day (1-12).
HH24	:Hour of day (0-23).
MI		:Minute (0-59).
SS		:Second (0-59).
SSSSS	:Seconds past midnight (0-86399)
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3. TO_NUMBER: It is used to convert the number which is in string format to the actual number