Oracle SQL statements are different from SQL statements in SQL Server.

Because the company's database uses Oracle, the operational data is now switched to Oracle. I am responsible for the processing of some website data, so I use oledb to connect to the data in the header. This is done by modifying and referencing the data, it is depressing that some SQL operations in Oracle are different from those in the original SQL Server. sometimes I will know why the error is wrong and I will keep searching for it. Later I will understand that the correct syntax in SQL Server may not be correct in Oracle, so I will ask Google for help, baidu can also. the best thing is to ask the boss, but he is busy with the old man. Please find it by yourself.
The first is to find the records of a specified number. SQL server uses Top N (number) to implement this (of course, this is not the only one, which is common here ), rownum is used in Oracle. for example, if one row is used, rownum <= 1 or rownum = 1 is used. If it is greater than one row, rownum <n is used. If rownum = N is used, I don't know why. it was a waste of time because I used = all the time. I found it later ......
I suddenly forgot what else, and then I wrote .....