Support many time functions

README.md

@@ -376,61 +376,61 @@ A list of ZetaSQL specifications and features supported by go-zetasqlite.
 ### Date functions
 
 - [x] CURRENT_DATE
-- [ ] EXTRACT
+- [x] EXTRACT
 - [x] DATE
 - [x] DATE_ADD
 - [x] DATE_SUB
 - [x] DATE_DIFF
 - [x] DATE_TRUNC
-- [ ] DATE_FROM_UNIX_DATE
+- [x] DATE_FROM_UNIX_DATE
 - [ ] FORMAT_DATE
-- [ ] LAST_DAY
+- [x] LAST_DAY
 - [x] PARSE_DATE
-- [ ] UNIX_DATE
+- [x] UNIX_DATE
 
 ### Datetime functions
 
 - [x] CURRENT_DATETIME
-- [ ] DATETIME
-- [ ] EXTRACT
-- [ ] DATETIME_ADD
-- [ ] DATETIME_SUB
-- [ ] DATETIME_DIFF
-- [ ] DATETIME_TRUNC
+- [x] DATETIME
+- [x] EXTRACT
+- [x] DATETIME_ADD
+- [x] DATETIME_SUB
+- [x] DATETIME_DIFF
+- [x] DATETIME_TRUNC
 - [ ] FORMAT_DATETIME
-- [ ] LAST_DAY
+- [x] LAST_DAY
 - [x] PARSE_DATETIME
 
 ### Time functions
 
 - [x] CURRENT_TIME
-- [ ] TIME
-- [ ] EXTRACT
-- [ ] TIME_ADD
-- [ ] TIME_SUB
-- [ ] TIME_DIFF
-- [ ] TIME_TRUNC
+- [x] TIME
+- [x] EXTRACT
+- [x] TIME_ADD
+- [x] TIME_SUB
+- [x] TIME_DIFF
+- [x] TIME_TRUNC
 - [ ] FORMAT_TIME
 - [x] PARSE_TIME
 
 ### Timestamp functions
 
 - [x] CURRENT_TIMESTAMP
-- [ ] EXTRACT
-- [ ] STRING
-- [ ] TIMESTAMP
-- [ ] TIMESTAMP_ADD
-- [ ] TIMESTAMP_SUB
-- [ ] TIMESTAMP_DIFF
-- [ ] TIMESTAMP_TRUNC
+- [x] EXTRACT
+- [x] STRING
+- [x] TIMESTAMP
+- [x] TIMESTAMP_ADD
+- [x] TIMESTAMP_SUB
+- [x] TIMESTAMP_DIFF
+- [x] TIMESTAMP_TRUNC
 - [ ] FORMAT_TIMESTAMP
 - [x] PARSE_TIMESTAMP
-- [ ] TIMESTAMP_SECONDS
-- [ ] TIMESTAMP_MILLIS
-- [ ] TIMEATAMP_MICROS
-- [ ] UNIX_SECONDS
-- [ ] UNIX_MILLIS
-- [ ] UNIX_MICROS
+- [x] TIMESTAMP_SECONDS
+- [x] TIMESTAMP_MILLIS
+- [x] TIMEATAMP_MICROS
+- [x] UNIX_SECONDS
+- [x] UNIX_MILLIS
+- [x] UNIX_MICROS
 
 ### Interval functions
 

internal/analyzer.go

@@ -69,6 +69,7 @@ func newAnalyzerOptions() *zetasql.AnalyzerOptions {
 		zetasql.FeatureV13DateTimeConstructors,
 		zetasql.FeatureV13ExtendedDateTimeSignatures,
 		zetasql.FeatureV12CivilTime,
+		zetasql.FeatureV12WeekWithWeekday,
 		zetasql.FeatureIntervalType,
 		zetasql.FeatureGroupByRollup,
 		zetasql.FeatureV13NullsFirstLastInOrderBy,

internal/function.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"regexp"
 	"strings"
+	"time"
 )
 
 func ADD(a, b Value) (Value, error) {
@@ -495,3 +496,56 @@ func MAKE_STRUCT(args ...Value) (Value, error) {
 		m:      fieldMap,
 	}, nil
 }
+
+func EXTRACT(t time.Time, part string) (Value, error) {
+	switch part {
+	case "ISOYEAR":
+		year, _ := t.ISOWeek()
+		return IntValue(year), nil
+	case "YEAR":
+		return IntValue(t.Year()), nil
+	case "MONTH":
+		return IntValue(t.Month()), nil
+	case "ISOWEEK":
+		_, week := t.ISOWeek()
+		return IntValue(week), nil
+	case "WEEK":
+		_, week := t.AddDate(0, 0, -int(t.Weekday())).ISOWeek()
+		return IntValue(week), nil
+	case "DAY":
+		return IntValue(t.Day()), nil
+	case "DAYOFYEAR":
+		return IntValue(t.YearDay()), nil
+	case "DAYOFWEEK":
+		return IntValue(int(t.Weekday()) + 1), nil
+	case "QUARTER":
+		day := t.YearDay()
+		const quarterDays = 91
+		switch {
+		case day <= quarterDays:
+			return IntValue(1), nil
+		case day <= quarterDays*2:
+			return IntValue(2), nil
+		case day <= quarterDays*3:
+			return IntValue(3), nil
+		}
+		return IntValue(4), nil
+	case "HOUR":
+		return IntValue(t.Hour()), nil
+	case "MINUTE":
+		return IntValue(t.Minute()), nil
+	case "SECOND":
+		return IntValue(t.Second()), nil
+	case "MILLISECOND":
+		return IntValue(t.Nanosecond() / int(time.Millisecond)), nil
+	case "MICROSECOND":
+		return IntValue(t.Nanosecond() / int(time.Microsecond)), nil
+	case "DATE":
+		return DateValue(t), nil
+	case "DATETIME":
+		return DatetimeValue(t), nil
+	case "TIME":
+		return TimeValue(t), nil
+	}
+	return nil, fmt.Errorf("failed to extract: undefined part %s", part)
+}