How to simulate two SQL Server date processing functions

It is very inconvenient to process dates in PHP, for example, to find the month of the difference between two dates? What should I do? File name: date. inc. php3 before using these two functions, you must first convert the date or date to the timestamp type. For example: $ todaymktime (0, 0, 0, date (m), date (d), date (Y); ***** simulate dateadd SQL Server in sqlserver

// It is inconvenient to process dates in PHP, for example, to find the month with a different date? What should I do?
// File name: date. inc. php3
// Before using these two functions, convert the date or date to the timestamp type.
// For example:
// $ Today = mktime (0, 0, 0, date ("m"), date ("d"), date ("Y "));

/***** Simulate the dateadd function in sqlserver *******
$ Part Type: string
Value range: year, month, day, hour, min, sec
Indicates the part of the date to be added.
$ N type: value
Indicates the amount to be added. you can decide which part to add based on $ part.
Negative
$ Datetime type: timestamp
Indicates the base number to be added.
Return type: timestamp
**************/
Function dateadd ($ part, $ n, $ datetime ){
$ Year = date ("Y", $ datetime );
$ Month = date ("m", $ datetime );
$ Day = date ("d", $ datetime );
$ Hour = date ("H", $ datetime );
$ Min = date ("I", $ datetime );
$ Sec = date ("s", $ datetime );
$ Part = strtolower ($ part );
$ Ret = 0;
Switch ($ part ){
Case "year ":
$ Year = $ n;
Break;
Case "month ":
$ Month = $ n;
Break;
Case "day ":
$ Day = $ n;
Break;
Case "hour ":
$ Hour = $ n;
Break;
Case "min ":
$ Min = $ n;
Break;
Case "sec ":
$ Sec = $ n;
Break;
Default:
Return $ ret;
Break;
}
$ Ret = mktime ($ hour, $ min, $ sec, $ month, $ day, $ year );
Return $ ret;
}

/***** Simulate the datediff function in sqlserver *******
$ Part Type: string
Value range: year, month, day, hour, min, sec
Indicates the part of the date to be added.
$ Date1, $ date2 type: timestamp
Two dates to be compared
Return type: numeric value
* ************** End *(*************/
Function datediff ($ part, $ date1, $ date2 ){
// $ Diff = $ date2-$ date1;
$ Year1 = date ("Y", $ date1 );
$ Year2 = date ("Y", $ date2 );
$ Mon2nd = date ("m", $ date2 );
$ Month1 = date ("m", $ date1 );
$ Day2 = date ("d", $ date2 );
$ Day1 = date ("d", $ date1 );
$ Hour2 = date ("d", $ date2 );
$ Hour1 = date ("d", $ date1 );
$ Min2 = date ("I", $ date2 );
$ Min1 = date ("I", $ date1 );
$ Sec2 = date ("s", $ date2 );
$ Sec1 = date ("s", $ date1 );

$ Part = strtolower ($ part );
$ Ret = 0;
Switch ($ part ){
Case "year ":
$ Ret = $ year2-$ year1;
Break;
Case "month ":
$ Ret = ($ year2-$ year1) * 12 $ mon2s-$ month1;
Break;
Case "day ":
$ Ret = (mktime (, 0, $ mon2, $ day2, $ year2)-mktime (, 0, $ month1, $ day1, $ year1 )) /(24x3600 );
Break;
Case "hour ":
$ Ret = (mktime ($ hour2, $ mon2, $ day2, $ year2)-mktime ($ hour1, $ month1, $ day1, $ year1 )) /3600;
Break;
Case "min ":
$ Ret = (mktime ($ hour2, $ min2, 0, $ mon2, $ day2, $ year2)-mktime ($ hour1, $ min1, 0, $ month1, $ day1, $ year1)/60;
Break;
Case "sec ":
$ Ret = $ date2-$ date1;
Break;
Default:
Return $ ret;
Break;
}
Return $ ret;
}

}