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@ -66,73 +66,73 @@
| a.TrimStart | ltrim(a) | ltrim(a) | ltrim(a) | 移除右侧指定字符 | | a.TrimStart | ltrim(a) | ltrim(a) | ltrim(a) | 移除右侧指定字符 |
### 日期对象 ### 日期对象
| 表达式 | MySql | SqlServer | PostgreSQL | 功能说明 | | 表达式 | MySql | SqlServer | PostgreSQL |
| - | - | - | - | - | | - | - | - | - |
| DateTime.Now | now() | getdate() | current_timestamp | 取本地时间 | | DateTime.Now | now() | getdate() | current_timestamp |
| DateTime.UtcNow | utc_timestamp() | getutcdate() | (current_timestamp at time zone 'UTC') | 取UTC时间 | | DateTime.UtcNow | utc_timestamp() | getutcdate() | (current_timestamp at time zone 'UTC') |
| DateTime.Today | curdate | convert(char(10),getdate(),120) | current_date | 取本地时间，日期部分 | | DateTime.Today | curdate | convert(char(10),getdate(),120) | current_date |
| DateTime.MaxValue | cast('9999/12/31 23:59:59' as datetime) | '1753/1/1 0:00:00' | '0001/1/1 0:00:00'::timestamp | 最大时间 | | DateTime.MaxValue | cast('9999/12/31 23:59:59' as datetime) | '1753/1/1 0:00:00' | '0001/1/1 0:00:00'::timestamp |
| DateTime.MinValue | cast('0001/1/1 0:00:00' as datetime) | '9999/12/31 23:59:59' | '9999/12/31 23:59:59'::timestamp | 最小时间 | | DateTime.MinValue | cast('0001/1/1 0:00:00' as datetime) | '9999/12/31 23:59:59' | '9999/12/31 23:59:59'::timestamp |
| DateTime.Compare(a, b) | a - b | a - b | extract(epoch from a::timestamp-b::timestamp) | 比较a和b的大小 | | DateTime.Compare(a, b) | a - b | a - b | extract(epoch from a::timestamp-b::timestamp) |
| DateTime.DaysInMonth(a, b) | dayofmonth(last_day(concat(a, '-', b, '-1'))) | datepart(day, dateadd(day, -1, dateadd(month, 1, cast(a as varchar) + '-' + cast(b as varchar) + '-1'))) | extract(day from (a || '-' || b || '-01')::timestamp+'1 month'::interval-'1 day'::interval) | 取指定年月份的总天数 | | DateTime.DaysInMonth(a, b) | dayofmonth(last_day(concat(a, '-', b, '-1'))) | datepart(day, dateadd(day, -1, dateadd(month, 1, cast(a as varchar) + '-' + cast(b as varchar) + '-1'))) | extract(day from (a || '-' || b || '-01')::timestamp+'1 month'::interval-'1 day'::interval) |
| DateTime.Equals(a, b) | a = b | a = b | a = b | 比较a和b相等 | | DateTime.Equals(a, b) | a = b | a = b | a = b |
| DateTime.IsLeapYear(a) | a%4=0 and a%100<>0 or a%400=0 | a%4=0 and a%100<>0 or a%400=0 | a%4=0 and a%100<>0 or a%400=0 | 判断闰年 | | DateTime.IsLeapYear(a) | a%4=0 and a%100<>0 or a%400=0 | a%4=0 and a%100<>0 or a%400=0 | a%4=0 and a%100<>0 or a%400=0 |
| DateTime.Parse(a) | cast(a as datetime) | cast(a as datetime) | a::timestamp | 转换日期类型 | | DateTime.Parse(a) | cast(a as datetime) | cast(a as datetime) | a::timestamp |
| a.Add(b) | date_add(a, interval b microsecond) | dateadd(millisecond, b / 1000, a) | a::timestamp+(b||' microseconds')::interval | 增加TimeSpan值 | | a.Add(b) | date_add(a, interval b microsecond) | dateadd(millisecond, b / 1000, a) | a::timestamp+(b||' microseconds')::interval | 增加TimeSpan值 |
| a.AddDays(b) | date_add(a, interval b day) | dateadd(day, b, a) | a::timestamp+(b||' day')::interval | 增加天数 | | a.AddDays(b) | date_add(a, interval b day) | dateadd(day, b, a) | a::timestamp+(b||' day')::interval |
| a.AddHours(b) | date_add(a, interval b hour) | dateadd(hour, b, a) | a::timestamp+(b||' hour')::interval | 增加小时 | | a.AddHours(b) | date_add(a, interval b hour) | dateadd(hour, b, a) | a::timestamp+(b||' hour')::interval |
| a.AddMilliseconds(b) | date_add(a, interval b*1000 microsecond) | dateadd(millisecond, b, a) | a::timestamp+(b||' milliseconds')::interval | 增加毫秒 | | a.AddMilliseconds(b) | date_add(a, interval b*1000 microsecond) | dateadd(millisecond, b, a) | a::timestamp+(b||' milliseconds')::interval |
| a.AddMinutes(b) | date_add(a, interval b minute) | dateadd(minute, b, a) | a::timestamp+(b||' minute')::interval | 增加分钟 | | a.AddMinutes(b) | date_add(a, interval b minute) | dateadd(minute, b, a) | a::timestamp+(b||' minute')::interval |
| a.AddMonths(b) | date_add(a, interval b month) | dateadd(month, b, a) | a::timestamp+(b||' month')::interval | 增加月 | | a.AddMonths(b) | date_add(a, interval b month) | dateadd(month, b, a) | a::timestamp+(b||' month')::interval |
| a.AddSeconds(b) | date_add(a, interval b second) | dateadd(second, b, a) | a::timestamp+(b||' second')::interval | 增加秒 | | a.AddSeconds(b) | date_add(a, interval b second) | dateadd(second, b, a) | a::timestamp+(b||' second')::interval |
| a.AddTicks(b) | date_add(a, interval b/10 microsecond) | dateadd(millisecond, b / 10000, a) | a::timestamp+(b||' microseconds')::interval | 增加刻度，微秒的1/10 | | a.AddTicks(b) | date_add(a, interval b/10 microsecond) | dateadd(millisecond, b / 10000, a) | a::timestamp+(b||' microseconds')::interval |
| a.AddYears(b) | date_add(a, interval b year) | dateadd(year, b, a) | a::timestamp+(b||' year')::interval | 增加年 | | a.AddYears(b) | date_add(a, interval b year) | dateadd(year, b, a) | a::timestamp+(b||' year')::interval |
| a.Date | cast(date_format(a, '%Y-%m-%d') as datetime) | convert(char(10),a,120) | a::date | 获取a的日期部分 | | a.Date | cast(date_format(a, '%Y-%m-%d') as datetime) | convert(char(10),a,120) | a::date |
| a.Day | dayofmonth(a) | datepart(day, a) | extract(day from a::timestamp) | 获取a在月的第几天 | | a.Day | dayofmonth(a) | datepart(day, a) | extract(day from a::timestamp) |
| a.DayOfWeek | dayofweek(a) | datepart(weekday, a) - 1 | extract(dow from a::timestamp) | 获取a在周的第几天 | | a.DayOfWeek | dayofweek(a) | datepart(weekday, a) - 1 | extract(dow from a::timestamp) |
| a.DayOfYear | dayofyear(a) | datepart(dayofyear, a) | extract(doy from a::timestamp) | 获取a在年的第几天 | | a.DayOfYear | dayofyear(a) | datepart(dayofyear, a) | extract(doy from a::timestamp) |
| a.Hour | hour(a) | datepart(hour, a) | extract(hour from a::timestamp) | 小时 | | a.Hour | hour(a) | datepart(hour, a) | extract(hour from a::timestamp) |
| a.Millisecond | floor(microsecond(a) / 1000) | datepart(millisecond, a) | extract(milliseconds from a::timestamp)-extract(second from a::timestamp)*1000 | 毫秒 | | a.Millisecond | floor(microsecond(a) / 1000) | datepart(millisecond, a) | extract(milliseconds from a::timestamp)-extract(second from a::timestamp)*1000 |
| a.Minute | minute(a) | datepart(minute, a) | extract(minute from a::timestamp) | 分钟 | | a.Minute | minute(a) | datepart(minute, a) | extract(minute from a::timestamp) |
| a.Month | month(a) | datepart(month, a) | extract(month from a::timestamp) | 月 | | a.Month | month(a) | datepart(month, a) | extract(month from a::timestamp) |
| a.Second | second(a) | datepart(second, a) | extract(second from a::timestamp) | 秒 | | a.Second | second(a) | datepart(second, a) | extract(second from a::timestamp) |
| a.Subtract(b) | timestampdiff(microsecond, b, a) | datediff(millisecond, b, a) * 1000 | (extract(epoch from a::timestamp-b::timestamp)*1000000) | 将a的值和b相减 | | a.Subtract(b) | timestampdiff(microsecond, b, a) | datediff(millisecond, b, a) * 1000 | (extract(epoch from a::timestamp-b::timestamp)*1000000) |
| a.Ticks | timestampdiff(microsecond, '0001-1-1', a) * 10 | datediff(millisecond, '1970-1-1', a) * 10000 + 621355968000000000 | extract(epoch from a::timestamp)*10000000+621355968000000000 | 刻度总数 | | a.Ticks | timestampdiff(microsecond, '0001-1-1', a) * 10 | datediff(millisecond, '1970-1-1', a) * 10000 + 621355968000000000 | extract(epoch from a::timestamp)*10000000+621355968000000000 |
| a.TimeOfDay | timestampdiff(microsecond, date_format(a, '%Y-%m-%d'), a) | '1970-1-1 ' + convert(varchar, a, 14) | extract(epoch from a::time)*1000000 | 获取a的时间部分 | | a.TimeOfDay | timestampdiff(microsecond, date_format(a, '%Y-%m-%d'), a) | '1970-1-1 ' + convert(varchar, a, 14) | extract(epoch from a::time)*1000000 |
| a.Year | year(a) | datepart(year, a) | extract(year from a::timestamp) | 年 | | a.Year | year(a) | datepart(year, a) | extract(year from a::timestamp) | 年 |
| a.Equals(b) | a = b | a = b | a = b | 比较a和b相等 | | a.Equals(b) | a = b | a = b | a = b |
| a.CompareTo(b) | a - b | a - b | a - b | 比较a和b大小 | | a.CompareTo(b) | a - b | a - b | a - b |
| a.ToString() | date_format(a, '%Y-%m-%d %H:%i:%s.%f') | convert(varchar, a, 121) | to_char(a, 'YYYY-MM-DD HH24:MI:SS.US') | 转换字符串 | | a.ToString() | date_format(a, '%Y-%m-%d %H:%i:%s.%f') | convert(varchar, a, 121) | to_char(a, 'YYYY-MM-DD HH24:MI:SS.US') |
### 时间对象 ### 时间对象
| 表达式 | MySql(微秒) | SqlServer(秒) | PostgreSQL(微秒) | 功能说明 | | 表达式 | MySql(微秒) | SqlServer(秒) | PostgreSQL(微秒) |
| - | - | - | - | - | | - | - | - | - |
| TimeSpan.Zero | 0 | 0 | - | 0微秒 | | TimeSpan.Zero | 0 | 0 | - | 0微秒 |
| TimeSpan.MaxValue | 922337203685477580 | 922337203685477580 | - | 最大微秒时间 | | TimeSpan.MaxValue | 922337203685477580 | 922337203685477580 | - |
| TimeSpan.MinValue | -922337203685477580 | -922337203685477580 | - | 最小微秒时间 | | TimeSpan.MinValue | -922337203685477580 | -922337203685477580 | - |
| TimeSpan.Compare(a, b) | a - b | a - b | - | 比较a和b的大小 | | TimeSpan.Compare(a, b) | a - b | a - b | - |
| TimeSpan.Equals(a, b) | a = b | a = b | - | 比较a和b相等 | | TimeSpan.Equals(a, b) | a = b | a = b | - |
| TimeSpan.FromDays(a) | a * 1000000 * 60 * 60 * 24 | a * 1000000 * 60 * 60 * 24 | - | a天的微秒值 | | TimeSpan.FromDays(a) | a * 1000000 * 60 * 60 * 24 | a * 1000000 * 60 * 60 * 24 | - |
| TimeSpan.FromHours(a) | a * 1000000 * 60 * 60 | a * 1000000 * 60 * 60 | - | a小时的微秒值 | | TimeSpan.FromHours(a) | a * 1000000 * 60 * 60 | a * 1000000 * 60 * 60 | - |
| TimeSpan.FromMilliseconds(a) | a * 1000 | a * 1000 | - | a毫秒的微秒值 | | TimeSpan.FromMilliseconds(a) | a * 1000 | a * 1000 | - |
| TimeSpan.FromMinutes(a) | a * 1000000 * 60 | a * 1000000 * 60 | - | a分钟的微秒值 | | TimeSpan.FromMinutes(a) | a * 1000000 * 60 | a * 1000000 * 60 | - |
| TimeSpan.FromSeconds(a) | a * 1000000 | a * 1000000 | - | a秒钟的微秒值 | | TimeSpan.FromSeconds(a) | a * 1000000 | a * 1000000 | - |
| TimeSpan.FromTicks(a) | a / 10 | a / 10 | - | a刻度的毫秒值 | | TimeSpan.FromTicks(a) | a / 10 | a / 10 | - |
| a.Add(b) | a + b | a + b | - | 增加值 | | a.Add(b) | a + b | a + b | - |
| a.Subtract(b) | a - b | a - b | - | 将a的值和b相减 | | a.Subtract(b) | a - b | a - b | - |
| a.CompareTo(b) | a - b | a - b | - | 比较a和b大小 | | a.CompareTo(b) | a - b | a - b | - |
| a.Days | a div (1000000 * 60 * 60 * 24) | a div (1000000 * 60 * 60 * 24) | - | 天数部分 | | a.Days | a div (1000000 * 60 * 60 * 24) | a div (1000000 * 60 * 60 * 24) | - |
| a.Hours | a div (1000000 * 60 * 60) mod 24 | a div (1000000 * 60 * 60) mod 24 | - | 小时部分 | | a.Hours | a div (1000000 * 60 * 60) mod 24 | a div (1000000 * 60 * 60) mod 24 | - |
| a.Milliseconds | a div 1000 mod 1000 | a div 1000 mod 1000 | - | 毫秒部分 | | a.Milliseconds | a div 1000 mod 1000 | a div 1000 mod 1000 | - |
| a.Seconds | a div 1000000 mod 60 | a div 1000000 mod 60 | - | 秒数部分 | | a.Seconds | a div 1000000 mod 60 | a div 1000000 mod 60 | - |
| a.Ticks | a * 10 | a * 10 | - | 刻度总数 | | a.Ticks | a * 10 | a * 10 | - |
| a.TotalDays | a / (1000000 * 60 * 60 * 24) | a / (1000000 * 60 * 60 * 24) | - | 总天数(含小数) | | a.TotalDays | a / (1000000 * 60 * 60 * 24) | a / (1000000 * 60 * 60 * 24) | - |
| a.TotalHours | a / (1000000 * 60 * 60) | a / (1000000 * 60 * 60) | - | 总小时(含小数) | | a.TotalHours | a / (1000000 * 60 * 60) | a / (1000000 * 60 * 60) | - |
| a.TotalMilliseconds | a / 1000 | a / 1000 | - | 总毫秒(含小数) | | a.TotalMilliseconds | a / 1000 | a / 1000 | - |
| a.TotalMinutes | a / (1000000 * 60) | a / (1000000 * 60) | - | 总分钟(含小数) | | a.TotalMinutes | a / (1000000 * 60) | a / (1000000 * 60) | - |
| a.TotalSeconds | a / 1000000 | a / 1000000 | - | 总秒数(含小数) | | a.TotalSeconds | a / 1000000 | a / 1000000 | - |
| a.Equals(b) | a = b | a = b | - | 比较a和b相等 | | a.Equals(b) | a = b | a = b | - |
| a.ToString() | cast(a as varchar) | cast(a as varchar) | - | 转换字符串 | | a.ToString() | cast(a as varchar) | cast(a as varchar) | - |
### 数学函数 ### 数学函数
| 表达式 | MySql | SqlServer | PostgreSQL | | 表达式 | MySql | SqlServer | PostgreSQL |