Oracle problem, 10 questions every day (11)

101. How to search for the first N record? Select * from Employee WHERE ROWNUM CONN INTERNAL; SQL> Show parameter processes; 103. DB_BLOCK_SIZE can be modified? Generally, not, not recommended Do this. 104. How to count the total number of records of two tables? SELECT (SELECT Count (ID) from AA) Total from Dual; 105. How to use the SQL statement to find the n value in a column? Select * from (Select T. *, Dense_Rank () over (Order By Sal) where rank = n;

106. How do I add 2 years when giving an existing date? SELECT Add_MontHS (Sysdate, 24) from Dual; 107. What does it mean for negative value? IT IS "HARMLESS". 108. What does Connect String refers to what? should be the service name in tnsnames.ora 109. How to expand how to expand REDO log size? Create a temporary Redolog group, then switch the log, delete the previous log, and create a new log. 110. Is the TABLESPACE not greater than 4G? There is no limit.