Char To Timestamp(Sys)

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Char To Timestamp(Sys)

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The Char to Timestamp function is one of the most frequently-used system functions, because it lets you create a timestamp out of any correctly formatted input string. Using this function, you can specify which parts of the timestamp string you wish to use in subsequent processing, and create a TIMESTAMP value containing only those. To do so, you specify a template that identifies the parts of the timestamp you want. For example, to use only year and month, you would specify 'yyyy-MM' .

The input date-time string can contain any parts of a full timestamp ('yyyy-MM-dd hh:mm:ss'). If all these elements are present in your input string, and 'yyyy-MM-dd hh:mm:ss' is the template you supply, then the input-string elements are interpreted in that order as year, month, day, hour, minute, and seconds, such as in '2009-09-16 03:15:24'. The yyyy cannot be uppercase; the hh can be uppercase to mean using a 24-hour clock. For the full range of valid specifiers, see Java SimpleDateFormat class.

SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP uses the template you specify as a parameter in the function call. The template causes the TIMESTAMP result to use only the parts of the input-date-time value that you specified in the template. Those fields in the resulting TIMESTAMP will then contain the corresponding data taken from your input-date-time string; fields not specified in your template will use default values (see below). The format of the template used by SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP is defined by the Java SimpleDateFormat class. See also the Date and Time patterns discussion in this SQLstream SQL Reference Guide.

5_2_indicator

Version 5.2 Feature

As of version 5.2, you no longer need to use the preface SYS_BOOT.MGMT.

The function-call syntax is as follows:

SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('<format_string>','<input_date_time_string>')

where

<format_ string> is the template you specify for the parts of <date_time_string> you want,

and

<input_date_time_string> is the original string that is being converted to a TIMESTAMP result.

Note that each string must be enclosed in single quotes and each element of the <input_date_time_string> must be in the range for its corresponding element in the template, otherwise no result is returned.

For example, the input-string-element whose position corresponds with MM must be an integer from 1 to 12, because anything else does not represent a valid month. Similarly, the input-string-element whose position corresponds with dd must be an integer from 1 to 31, because anything else does not represent a valid day. (However, if MM is 2, dd cannot be 30 or 31, because February never has such days.)

For hours, minutes, or seconds, the default starting value is zero, so when those specifiers are omitted from the template, zeroes are substituted. For months or days, the default starting value substituted for the omitted parts is 01.

For example, using '2009-09-16 03:15:24' as your input string, you can obtain a TIMESTAMP containing only the date, with zeros for the other fields such as hours, minutes, or seconds:

SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM-dd','2009-09-16 03:15:24').

 

The result would is TIMESTAMP 2009-09-16 00:00:00.

Another example:

If the call had kept hours and minutes in the template while omitting months, days, and seconds, as illustrated in the following call

--- --- SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-hh-mm','2009-09-16 03:15:24')

 

then the resulting TIMESTAMP would be 2009-01-01 03:15:00.

Template strings to create specific output TIMESTAMPS shows further illustrative examples of templates and input strings used to create the indicated output TIMESTAMPs.

Note: Input string MUST use the form 'yyyy-MM-dd hh:mm:ss' or a subset or reordering thereof. As a result, using an input string like 'Wednesday, 16 September 2009 03:15:24' will NOT work, meaning that no output will result.

About Delimiters and Values

Delimiters in the template must match those in the input string and values in the input string must be acceptable for the template specifiers to which they correspond.

As a general convention, a colon is used to separate hours from minutes, and minutes from seconds. Similarly, the general convention is to use a dash or slash to separate years from months and months from days.

For example, the following template has values that line up correctly with the input string.

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('MM/dd/yy hh:mm:ss','09/16/11 03:15:24') );

'EXPR$0'

'2011-09-16 03:15:24'

1 row selected

 

If values in the input string are not acceptable for the template specifiers to which they correspond, the result fails, as in the following example.

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('MM/dd/yy hh:mm:ss','2009/09/16 03:15:24') );

'EXPR$0'

No rows selected

 

This example returns no rows because 2009 is not an acceptable value for months, which is the first specifier (MM) in the template.

Omissions in the supplied string can cause the template value 'yyyy' to produce logical but unintended or unexpected results. The following examples each return an erroneous year, but one that derives directly from the first element in the supplied string.

0: jdbc:sqlstream:> VALUES(SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy','09-16 03:15'));

'EXPR$0'

'0009-01-01 00:00:00'

1 row selected

0: jdbc:sqlstream:> VALUES(SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy','16 03:15'));

'EXPR$0'

'0016-01-01 00:00:00'

1 row selected

 

Examples using templates to create TIMESTAMPS

The order of the template must match the input string. That means that you cannot specify "hh" after "yyyy" and expect the method to find the hour automatically. For example, the following template specifies years first, then hours, then minutes, and returns an erroneous result.

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-hh-mm','2009-09-16 03:15:24'));

'EXPR$0'

'2009-01-01 09:16:00'

1 row selected

 

Since the specifiers for months and days are not present in the template, their values in the input string were ignored, with 01 substituted for both values in the output TIMESTAMP. The template specified hours and minutes as the second and third input values, so 09 became the hours and 16 became the minutes. No specifier was present for seconds, so 00 was used.

The years specifier can be alone or after a delimiter matching the input string shows the end of the years specifier, with one of the hours:minutes:seconds specifiers:

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy','2009-09-16 03:15:24') );

'EXPR$0'

'2009-01-01 00:00:00'

1 row selected

 

In contrast, the template below fails because it has a space-as-delimiter before the "hh" rather than the dash delimiter used in the input string's date specification.

 

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy hh','2009-09-16 03:15:24') );

'EXPR$0'

No rows selected

 

The four templates below work because they use the same delimiter to separate the years specifier from the next specifier as is used in the input string's date specification (dash in the first case, space in the second, slash in the third, and dash in the fourth).

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-hh','2009-09-16 03:15:24') );

'EXPR$0'

'2009-01-01 09:00:00'

1 row selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy hh','2009 09 16 03:15:24') );

'EXPR$0'

'2009-01-01 09:00:00'

1 row selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy/hh','2009/09/16 03:15:24') );

'EXPR$0'

'2009-01-01 09:00:00'

1 row selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-mm','2009-09-16 03:15:24') );

'EXPR$0'

'2009-01-01 00:09:00'

1 row selected

 

Using SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP to convert a string to a timestamp

When the input string is not in the appropriate format to be CAST, you can use the SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP method. It has the additional advantage that you can specify which parts of the timestamp string you wish to use in subsequent processing, and create a TIMESTAMP value containing only those. To do so, you specify a template that identifies which parts you want, such as 'yyyy-MM' to use only the year and month parts.

The input-date-time string-to-be-converted can contain all or any parts of a full timestamp, that is, values for any or all of the standard elements ('yyyy-MM-dd hh:mm:ss'). If all these elements are present in your input string, and 'yyyy-MM-dd hh:mm:ss' is the template you supply, then the input-string elements are interpreted in that order as year, month, day, hour, minute, and seconds, such as in '2009-09-16 03:15:24'. The yyyy cannot be uppercase; the hh can be uppercase to mean using a 24-hour clock. For many examples of valid specifiers, see the table entitled Template strings to create specific output TIMESTAMPS and the examples topic. For the full range of valid specifiers, see Java SimpleDateFormat class.

SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP uses the template you specify as a parameter in the function call. The template causes the TIMESTAMP result to use only the parts of the input-date-time value that you specified in the template. Those fields in the resulting TIMESTAMP will then contain the corresponding data taken from your input-date-time string; fields not specified in your template will use default values (see below). The format of the template used by SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP is defined by Java SimpleDateFormat class, at which link all the specifiers are listed, some with examples. See also the Date and Time patterns discussion in this SQLstream SQL Reference Guide.

The function-call syntax is as follows:

 SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('<format_string>','<input_date_time_string>')

where

<format_ string> is the template you specify for the parts of <date_time_string> you want,

and

<input_date_time_string> is the original string that is being converted to a TIMESTAMP result.

Note that each string must be enclosed in single quotes; AND that each element of the <input_date_time_string> must be in the range for its corresponding element in the template; otherwise no result is returned.

Examples:

The input-string-element whose position corresponds with MM must be an integer from 1 to 12, because anything else does not represent a valid month.
The input-string-element whose position corresponds with dd must be an integer from 1 to 31, because anything else does not represent a valid day.
oHowever, if MM is 2, dd cannot be 30 or 31, because February never has such days.

Note that for hours, minutes, or seconds, the default starting value is zero, so when those specifiers are omitted from the template, zeroes are substituted.

However, for months or days, the default starting value substituted for the omitted parts is 01.

For example, using '2009-09-16 03:15:24' as your input string, you can obtain a TIMESTAMP containing only the date, with zeros for the other fields such as hours, minutes, or seconds, by specifying

 SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM-dd','2009-09-16 03:15:24').

 

The result would be the TIMESTAMP 2009-09-16 00:00:00.

Another example:

If the call had kept hours and minutes in the template while omitting months, days, and seconds, as illustrated in the following call --- --- SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-hh-mm','2009-09-16 03:15:24') --- --- then the resulting TIMESTAMP would be 2009-01-01 03:15:00.

The table below, Template Strings to Create Specific Output TIMESTAMPS, shows further examples of templates and input strings used to create the indicated output TIMESTAMPs.
Template Strings to Create Specific Output Timestamps

Template (and comments)

Input String

Output TIMESTAMP

'yyyy-MM-dd hh:mm:ss'

'2009-09-16 03:15:24'

'2009-09-16 03:15:24'

 

Comment: Input string MUST use the form 'yyyy-MM-dd hh:mm:ss' or a subset or reordering thereof; using an input string like 'Wednesday, 16 September 2009 03:15:24' will NOT work, meaning that no output will result.

'yyyy-mm'

'2012-02-08 07:23:19'

'2012-01-01 00:02:00'

 

Comment: The template above specifies only year first and minutes second, so the second element in the input string ("02") is used as minutes.

Default values are used for Month and Day ("01") and for hours and seconds ("00").

'yyyy-ss-mm'

'2012-02-08 07:23:19'

'2012-01-01 00:08:02'

 

Comment: The template above specifies only year, seconds, and minutes, in that order, so the second element in the input string ("02") is used as seconds and the third as minutes ("08"). Default values are used for Month and Day ("01") and for hours ("00").

'MMM dd, yyyy'

'March 7, 2010'

'2010-03-07 00:00:00'

 

Comment: MMM in the template above matches "March"; the template's 'comma space' matches the input string.

--- --- If the template lacks the comma, so must the input string, or there is no output;

--- --- If the input string lacks the comma, so must the template.

'MMM dd,'

'March 7, 2010'

'1970-03-07 00:00:00'

 

Comment: Note that the template above doesn't use a year specifier, causing the output TIMESTAMP to use the earliest year in this epoch, 1970.

'MMM dd,y'

'March 7, 2010'

'2010-03-07 00:00:00'

 

Comment: Using the template above, if the input string were 'March 7, 10', the output TIMESTAMP would be '0010-03-07 00:00:00'.

'M-d'

'2-8'

'1970-02-08 00:00:00'

 

Comment: Absent a yyyy specifier in the template, as above, the earliest year in this epoch (1970) is used.

An input string of '2-8-2012' would give the same result; using '2012-2-8' would give no result because 2012 is not a valid month.

'MM-dd-yyyy'

'06-23-2012 10:11:12'

'2012-06-23 00:00:00'

 

Comment: Dashes as delimiters (as above) are fine, if template and input both use them in the same positions. Since the template omits hours, minutes, and seconds, zeroes are used in the output TIMESTAMP.

'dd-MM-yy hh:mm:ss'

'23-06-11 10:11:12'

'2011-06-23 10:11:12'

 

Comment: You can have the specifiers in any order as long as that order matches the meaning of the input string you supply, as above. The template and input string of the next example below have the same meaning (and the same output TIMESTAMP) as this example, but they specify months before days and seconds before hours.

'MM-dd-yy ss:hh:mm'

'06-23-11 12:10:11'

'2011-06-23 10:11:12'

 

Comment: In the template used above, the order of the month and day specifiers is reversed from the example just above, and the specifier for seconds is before hours instead of after minutes; but because the input string also puts months before days and seconds before hours, the meaning (and the output TIMESTAMP) is the same as the example ABOVE.

'yy-dd-MM ss:hh:mm'

'06-23-11 12:10:11'

'2006-11-23 10:11:12'

 

Comment: The template used above reverses (compared to the prior example above) the years and months specifiers, while the input string remains the same. In this case, the output TIMESTAMP uses the first element of the input string as the years, the second as the days, and the third as the months.

'dd-MM-yy hh:mm'

'23-06-11 10:11:12'

'2011-06-23 10:11:00'

 

Comment: With seconds omitted in the template, as above, the output TIMESTAMP uses 00 seconds. Any number of y specifiers produces the same result; but if the input string inadvertently uses a 1 instead of 11 for the year, as in '23-06-1 10:11:12', then the output TIMESTAMP becomes '0001-06-23 10:11:00'.

'MM/dd/yy hh:mm:ss'

'12/19/11 10:11:12'

 

'12/19/11 12:11:10'

'2011-12-19 10:11:12'

 

'2011-12-19 00:11:10'

 

Comment: Slashes as delimiters are fine, if template and input both use them in the same positions, as above; otherwise, no output.

Using specifier hh, input times of 12:11:10 and 00:11:10 have the same meaning as a time in the morning.

'MM/dd/yy HH:mm:ss'

'12/19/11 12:59:59'

'12/19/11 21:08:07'

'2011-12-19 12:59:59'

'2011-12-19 21:08:07'

 

(The input-string values '2011-12-19 00:11:12' or '2011-12-19 12:11:12' would fail with this template because '2011' is not a month, as required/expected by the template-string 'MM/dd/yy HH:mm:ss'.)

 

However, changing the template gives useful output:

 

values(cast(SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('y/MM/dd HH:mm:ss', '2011/12/19 00:11:12') as varchar(19)));

'EXPR$0'

'2011-12-19 00:11:12'

1 row selected

'12/19/11 00:11:12' would fail with the above template ('y/MM/dd'), since 19 is not a valid month; supplying '12/11/19 00:11:12' works.

'2011-12-19 12:11:12' would fail as input because dashes don't match the slashes in the template ; '2011/12/19 12:11:12' works.

 

Comment:

Note that for times after 12 noon, that is, for afternoon and evening times, the hours specifier must be HH instead of hh, and the input string must specify the afternoon or evening hour in 24-hour clock time, hours running from 00 to 23.

--- --- Using specifier HH, input times of 12:11:10 and 00:11:10 have different meanings, the first as a time in the afternoon and the second as a time in the morning.

--- --- Using the specifier hh, the times from 12:00 through 11:59:59 are morning times:

--- --- Given the specifiers hh:mm:ss, the output TIMESTAMP will include '00:09:08' in the morning for both input string '12:09:08' and input string '00:09:08';

--- --- whereas

--- --- Given the specifiers HH:mm:ss, the output TIMESTAMP for input string '00:09:08' in the morning will include '00:09:08'

--- --- and the output TIMESTAMP for input string '12:09:08' in the afternoon will include '12:09:08'.

Additional examples using templates to create TIMESTAMPS

The examples below illustrate using various templates with SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP, including some common misunderstandings.

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-hh-mm','2009-09-16 03:15:24'));

'EXPR$0'

'2009-01-01 09:16:00'

1 row selected

 

Note that the fields in the input string above were used in the order given by the specifiers in the template, as defined by the dashes-as-delimiters in both template and input string: years first, then hours, then minutes. Since the specifiers for months and days are not present in the template, their values in the input string were ignored, with 01 substituted for both values in the output TIMESTAMP. The template specified hours and minutes as the second and third input values, so 09 became the hours and 16 became the minutes. No specifier was present for seconds, so 00 was used.

The years specifier can be alone or, after a delimiter matching the input string shows the end of the years specifier, with one of the hours:minutes:seconds specifiers:

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy','2009-09-16 03:15:24') );

'EXPR$0'

'2009-01-01 00:00:00'

1 row selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy hh','2009-09-16 03:15:24') );

'EXPR$0'

No rows selected

 

The template above fails because it has a space-as-delimiter before the "hh" rather than the dash delimiter used in the input string's date specification;

whereas the four templates below work because they use the same delimiter to separate the years specifier from the next specifier as is used in the input string's date specification (dash in the first case, space in the second, slash in the third, and dash in the fourth).

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-hh','2009-09-16 03:15:24') );

'EXPR$0'

'2009-01-01 09:00:00'

1 row selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy hh','2009 09 16 03:15:24') );

'EXPR$0'

'2009-01-01 09:00:00'

1 row selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy/hh','2009/09/16 03:15:24') );

'EXPR$0'

'2009-01-01 09:00:00'

1 row selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-mm','2009-09-16 03:15:24') );

'EXPR$0'

'2009-01-01 00:09:00'

1 row selected

 

However, if the template specifies months (MM), it cannot then specify hours, minutes, or seconds unless days are also specified:

Template specifying years and months only, thus omitting days/hours/minutes/seconds from the resulting TIMESTAMP:

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM','2009-09-16 03:15:24') );

'EXPR$0'

'2009-09-01 00:00:00'

1 row selected

 

The next two templates fail, lacking a 'days' specifier:

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM hh','2009-09-16 03:15:24') );

'EXPR$0'

No rows selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM hh:','2009-09-16 03:15:24') );

'EXPR$0'

No rows selected

 

The next three succeed, using a 'days' specifier:

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM-dd hh','2009-09-16 03:15:24') );

'EXPR$0'

'2009-09-16 03:00:00'

1 row selected

 

The template above, 'yyyy-MM-dd hh', specifies only hours (hh) without minutes or seconds. Since hh is the 4th token/element of the template, its value is to be taken from the 4th token/element of the input string '2009-09-16 03:15:24' ; and that 4th element is 03, then used as the value output for hours. Since neither mm or ss is specified, the default or initial values defined as the starting point for mm and ss are used, which are zeroes.

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM-dd ss','2009-09-16 03:15:24') );

'EXPR$0'

'2009-09-16 00:00:03'

1 row selected

 

The template above, 'yyyy-MM-dd ss', specifies that the 4th token/element of the input string is to be used as seconds (ss). The 4th element of the input string '2009-09-16 03:15:24' is 03, which becomes the value output for seconds as specified in the template; and since neither hh nor mm is specified in the template, their default or initial values are used, which are zeroes.

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM-dd mm','2009-09-16 03:15:24') );

'EXPR$0'

'2009-09-16 00:03:00'

1 row selected

 

The template above, 'yyyy-MM-dd mm', specifies that the 4th token/element of the input string is to be used as minutes (mm). The 4th element of the input string '2009-09-16 03:15:24' is 03, which becomes the value output for minutes as specified in the template; and since neither hh nor ss is specified in the template, their default or initial values are used, which are zeroes.

Further failures, lacking a 'days' specifier:

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM- mm','2009-09-16 03:15:24') );

'EXPR$0'

No rows selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM   mm','2009-09-16 03:15:24') );

'EXPR$0'

No rows selected

values (SYS_BOOT.MGMT.CHAR_TO_TIMESTAMP('yyyy-MM   hh','2009-09-16 03:15:24') );

'EXPR$0'

No rows selected