Обсуждение: please review source(SQLServer compatible)

Dear all，

Our application will be switched from SQL Server to PostgreSQL.
However, a few functions are not supported yet. So we decided to extend it.

The functions are as following:

1.SQL statement support
INSERT statement without INTO keyword
DELETE statement without FROM keywork
2.Build-in function
SQUARE
CHAR
CHARINDEX
LEN
REPLICATE
SPACE
STR
STUFF
CONVERT
DATALENGTH
DATEADD
DATEDIFF
DATEPART
DAY
MONTH
YEAR
EOMONTH
GETDATE
SYSDATETIME
3.Operator
operator !< (Not Less Than)
operator !> (Not Greater Than)
operator + (String Concatenation)
4.Other
DataType support(smalldatetime,datetime,datatime2,uniqueidentifer)
Date, Time, and Timestamp Escape Sequences ODBC Scalar Functions
OCTET_LENGTH
CURRENT_DATE
CURRENT_TIME

The extended functions are almost completed but your opinion is very important to us.
Would you please help us to review the extended source?

The attachments is the diff source.

Thank you very much.

Best wishes~
Sincerely yours, rohto.david