Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

Basic SQL Interview Questions

-
1. What is difference between decode and case?
2. How will you delete duplicate records?
3. how will select first 5 records from a table?
4. what are the psedu columns?
5. Difference between delete and truncate?
6. What are the type of constraints?
7. Under which constraints the index will be created?
8. What is the difference between union and union all?
9. How will you fetch nth max salary?
10. Difference between inner join and outer join?

Comments

Post a Comment

Popular posts from this blog

How to find the server is whether standby (slave) or primary(master) in Postgresql replication ?

-
Method 1 You can check the mode of the server using "pg_controldata". [pgsql@test~]$ pg_controldata /usr/local/pgsql/data84/ Database cluster state: in archive recovery --> This is Standby Database Database cluster state: in production --> This is Production Database [Master] Method 2 You can use pg_is_in_recovery() which returns True if recovery is still in progress(so the server is running in standby mode or slave) postgres=# select pg_is_in_recovery(); pg_is_in_recovery ------------------- t (1 row) If Return    false   so the server is running in primary mode or master postgres=# select pg_is_in_recovery(); pg_is_in_recovery ------------------- f (1 row)
Read more

spfile and pfile errors

-
SQL> create pfile='/home/oracle/karan/admin/pfile/initclone.ora' from spfile; create pfile='/home/oracle/karan/admin/pfile/initclone.ora' from spfile * ERROR at line 1: ORA-01565: error in identifying file '?/dbs/spfile@.ora' ORA-27037: unable to obtain file status Linux Error: 2: No such file or directory Additional information: 3 SQL> show parameter spfile; NAME                                 TYPE        VALUE ------------------------------------ ----------- ------------------------------ spfile                               string SQL> create spfile=   2   SQL> create spfile='/home/oracle/karan/admin/pfile/initclone.ora' from pfile; create spfile='/home/oracle/karan/admin/pfile/initclone.ora' from pfile * ERROR at line 1: ORA-01078: failure in processing system parameters LRM-00109: could not open parameter file '/oraeng/app/oracle/product/11.2.0/dbs/initkiruba.ora' SQL> create spfile from pfile; create spfile from pfil
Read more

How to Get Table Size, Database Size, Indexes Size, schema Size, Tablespace Size, column Size in PostgreSQL Database

-
In this post, I am sharing few important function for finding the size of database, table and index in PostgreSQL. Finding object size in postgresql database is very important and common. Is it very useful to know the exact size occupied by the object at the tablespace. The object size in the following scripts is in GB. The scripts have been formatted to work very easily with PUTTY SQL Editor. 1. Checking table size excluding table dependency: SELECT pg_size_pretty(pg_relation_size('mhrordhu_shk.mut_kharedi_audit')); pg_size_pretty ---------------- 238 MB (1 row) 2. Checking table size including table dependency: SELECT pg_size_pretty(pg_total_relation_size('mhrordhu_shk.mut_kharedi_audit')); pg_size_pretty ---------------- 268 MB (1 row) 3. Finding individual postgresql database size SELECT pg_size_pretty(pg_database_size('db_name')); 4. Finding individual table size for postgresql database -including dependency index: SELECT pg_size_pretty(pg_total_rel
Read more

2017 Shortern URL - Other Website Like ADFOC.US

-
Image
These are the lists of top paying url shortening websites that are similar to Adfoc.us or Shrink url Websites like Adfoc.us. The websites are similar in the sense that you can use the same pattern of registration and earnings for all them, but the only difference is the amount of money each pays to its members and also the percentage of earnings from their referral programs. 1. ADF.LY – Free Url Shortening similar to adfocus that will pay you $4 for 1000 clicks on your shorten url. You can Also refer your friends and earn 20% of their earnings for life. Their payment is quick and consistant. Paypal Or Alertpay. It’s legit and very popular. JOIN  HERE It’s legit and very popular. JOIN  HERE Payment Options Details :- Payout for 1000 Views: Upto $9 Minimum Payout: $5 Referral Commission: 20% Payment Options:Payoneer, Payza Payment Time : Daily and On Request You can Withdraw money Following Acc
Read more

ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated ORA-01262: Stat failed on a file destination directory Linux-x86_64 Error: 2: No such file or directory

-
While I start my database with my initialization parameter it fails with oracle error Solution :- su oracle run environment variable sqlplus / as sysdba SQL>create pfile from spfile; Then remove or comment below line in pfile db_recovery_file_dest Save and exit su oracle run environment variable sqlplus / as sysdba SQL>startup mount; ORACLE instance started. Total System Global Area 1068937216 bytes Fixed Size 2166536 bytes Variable Size 427819256 bytes Database Buffers 624951296 bytes Redo Buffers 14000128 bytes it should became the mount stage then open the DB as follows SQL>alter database open; Database altered.
Read more