ORA-00942 is one of the many errors which Oracle developer ,DBA often gets. Lets first look at the OERR output Cause: The table or view entered does not exist, a synonym that is not allowed here was used, or a view was referenced where a table is required. Existing user tables and views can be listed by querying the data dictionary. Certain privileges may be required … Continue reading How to Solve ORA-00942 table or view does not exist
Last updated on July 12th, 2018 at 05:51 pmDescription : ORA-00936 missing expression is one of the common error everybody working in Oracle Sql must have faced some time. This generally happens when you omit important thing in the Sql statement i.e you left out an important chunk of what you were trying to run Reference : Oracle documentation Cause This Oracle error is mainly related … Continue reading How to resolve the ORA-00936 missing expression
Last updated on July 13th, 2018 at 05:20 amORA-01017 is one of the common error seen in PLSQL programs. Here is what documentation says about this error Here are the checklist to run to resolve the ORA-01017 error The main issue with an ORA-01017 error is an invalid user ID and passwords combination. You have to make sure ,you are entering the right password Incase … Continue reading ORA-01017: invalid username/password; logon denied Tips
Last updated on July 13th, 2018 at 09:00 amORA-29913 is one of the common error when working with external tables in Oracle database. We would be looking at various ways the error can be produced and what can be done to resolve the error External File not found or permission incorrect SQL> select * from Scott.example_external_table; select * from example_external_table * ERROR at line 1: … Continue reading How to resolve ORA-29913 with external tables
We use grep command to search for strings in the Unix Operation system. Now the same things on Windows can be done using these three free tools. These tools can do many work same as Grep command. Find command Lets check out some command tasklist|find “notepad” The below command searches for string in all the files ending .txt find “string name” *.txt findstr command It … Continue reading Grep equivalent in Windows to search text
Sql SubQueries 1) A Subquery or Nested query is a query within another SQL query and embedded within the WHERE clause. A subquery is a query within a query 2) A subquery is used to return data that will be used in the main query as a condition to further restrict the data to be retrieved. 3) Subqueries answer the queries that have multiple parts. … Continue reading Sql Subqueries : Single, Multiple, Scalar and Correlated
Sometimes you need to display data from multiple tables. In order to perform that you need to link one table to another table.There are various ways in which we can obtain data from Multiple tables.Here I would be focusing on Oracle Joins.This is valid for in general any Sql Joins also Oracle Joins A Oracle Joins ( Sql Joins) is a query that combines rows from … Continue reading What are Oracle Joins (Sql Joins)?
Using Sql Set Operators(Union,Union All,Intersect and Minus/Except) Sql Set operators can be used to select data from multiple tables. They combine the results of two or more queries. When using the Set operators a) Each SELECT clause must have the same number of column b) Column must be of same data-type c) Column should be specified in the same order in all the select clauses. … Continue reading Sql Set Operators: Union,Union All,Intersect and Minus
Last updated on June 23rd, 2018 at 07:11 amWhat is materialized views in oracle A materialized view is a database object that contains the results of a query. It is different from simple view .These materialized view have data stored and when you query the materialized view,it returns data from the data stored. The FROM clause of the query can name tables, views, and other … Continue reading what is materialized views in oracle?
ORA-00904: invalid identifier is one of the common error seen. Reference: Oracle documentation One of the most common cause of this error Invalid identifier means the column name entered is either missing or invalid. It also Some time comes when you used reserved word in Oracle database. Check List to resolve the ORA-00904 error It comes when you put extra comma in the create table … Continue reading How to resolve ORA-00904: invalid identifier
Useful and common MySQL queries for the developer and DBA’s 1)How to create mysql database mysql> create database techdb; mysql> use techdb; 2) How to create table in mysql database? .How to show the structure of the table after creation Here is the example for table creation in MySQL database 1) We need to first get into database use techdb; 2) Create table using below … Continue reading Most Common MySQL queries
Introduction to sed command in Unix/Linux sed – Stream EDitor – works as a filter processing input line by line. Sed reads one line at a time, chops off the terminating newline, puts what is left into the pattern space (buffer) where the sed script can process it (often using regular expressions), then if there anything to print – sed appends a newline and prints … Continue reading Awesome sed command in Linux/Unix with examples