*: basic support for builtin function STR_TO_DATE #2078
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| if date == "" { | ||
| return nil | ||
| } | ||
| return errors.New("not enough data in date") |
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I test mysql behavior and find it never report error, just return NULL on fail.
I'll change to that.
| // Just one character. | ||
| if len(format) == 1 { | ||
| if format[0] == '%' { | ||
| return "", "", errors.New("bad format") |
| @@ -673,6 +675,416 @@ func builtinFromUnixTime(args []types.Datum, _ context.Context) (d types.Datum, | |||
| return builtinDateFormat([]types.Datum{d, args[1]}, nil) | |||
| } | |||
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| // strToDate convert date string according to format, return true on success, | |||
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builtinDateFormat would return a NULL datum if input date and format don't match, so we don't need return error
| ) | ||
| goTime = mysql.ZeroTime | ||
| if !strToDate(&goTime, date, format) { | ||
| d.SetNull() |
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This line may be useless, KindNull equals to 0 which is a default value.
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I prefer d.SetNull() here explicitly, it can remind us this function return NULL if strToDate fail...
depend on KindNull == 0 is not that reliable on some scenes
| if format[0] == '%' { | ||
| return "", "", false | ||
| } | ||
| return format[:1], format[1:], true |
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Will return format, "", true be more explicit?
| @@ -580,3 +580,31 @@ func (s *testEvaluatorSuite) TestDateArith(c *C) { | |||
| } | |||
| } | |||
| } | |||
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| func (s *testEvaluatorSuite) TestStrToDate(c *C) { | |||
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Add a test case for %a %b %c %D.
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it would be done in next PR
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| if len(input) >= 3 { | ||
| dayName := input[:3] | ||
| if day, ok := weekdayAbbrev[dayName]; ok { | ||
| timeSetDay(t, int(day)) |
| return format[:1], format[1:], true | ||
| } | ||
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| func skipWhiteSpace(input string) string { |
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Shall we skip the spaces at the end of string?
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Indeed, strToDate will skip any spaces, including the end
| return strToDate(t, dateRemain, formatRemain) | ||
| } | ||
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| func getFormatToken(format string) (token string, remain string, succ bool) { |
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add comments for this function.
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why?
this is not an exported function and very easy to understand, just as the function name says~
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I don't quite understand the meanings of "token" and "remain" without reading the MySQL manual.
| func abbreviatedWeekday(t *time.Time, input string) (string, bool) { | ||
| if len(input) >= 3 { | ||
| dayName := input[:3] | ||
| if _, ok := weekdayAbbrev[dayName]; ok { |
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I'll confirm the behavior of MySQL, in the next PRs
Currently this function is not really supported, as our time representation is not compatible with mysql.
| goTime time.Time | ||
| ) | ||
| goTime = types.ZeroTime | ||
| if !strToDate(&goTime, date, format) { |
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Shall we define a struct to call strToData, I think it's tooooo ugly to pass a pointer to get result
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Ugly? it's very common in C, and C-family languages. and Go is one of C-family
struct timeData {...}
var d timeData
d.strToDate() ??
I think it's ... Poor man's object ...
| @@ -673,6 +675,328 @@ func builtinFromUnixTime(args []types.Datum, _ context.Context) (d types.Datum, | |||
| return builtinDateFormat([]types.Datum{d, args[1]}, nil) | |||
| } | |||
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| // strToDate converts date string according to format, return true on success, | |||
| } | ||
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| func monthNumeric(t *time.Time, input string) (string, bool) { | ||
| // TODO: this code is ugly! |
| if len(input) >= 3 { | ||
| dayName := input[:3] | ||
| if _, ok := weekdayAbbrev[dayName]; ok { | ||
| // TODO: we need refact mysql time to support this |
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LGTM |
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| func monthNumeric(t *time.Time, input string) (string, bool) { | ||
| // TODO: This code is ugly! | ||
| for i := 12; i >= 0; i-- { |
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Why i >= 0, month 0 is valid?
| } | ||
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| func dayOfMonthNumericTwoDigits(t *time.Time, input string) (string, bool) { | ||
| v, succ := parseTwoDigits(input) |
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mysql behavior:
mysql> select str_to_date('2016 02 31', '%Y %m %D');
+---------------------------------------+
| str_to_date('2016 02 31', '%Y %m %D') |
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| 2016-02-31 |
+---------------------------------------+
1 row in set (0.00 sec)
mysql permit invalid date, while Go can't...and that why we need refact.
Of course, I'll be glad if you also review this PR #2098
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LGTM |
str_to_date('20161122165022','%Y%m%d%H%i%s')many specifiers in the format string are not supported yet
and more test will be add in next PR