Oracle development languages
Oracle programmers, coders and developers can get news, tips and advice about the various development languages used with Oracle databases and Oracle applications, including SQL, PL/SQL, stored procedures, Java and J2EE, XML and Web services.
Top Stories
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Podcast
27 Dec 2022
What's behind the low-code/no-code development trend in ERP?
Holger Mueller of Constellation Research says low-code/no-code development tools from ERP vendors offer significant benefits to both professional developers and non-technical business users. Continue Reading
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Tip
18 Jul 2022
A quick glance at the history of C programming languages
Since C hit the scene in 1972, the language has continuously evolved to stay relevant in modern development. We examine C's history and why it's still relevant. Continue Reading
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News
05 Apr 2021
Supreme Court sides with Google in Oracle API copyright suit
The Supreme Court ruled 6-2 that Java APIs used in Android phones are not subject to American copyright law, ending a longstanding legal battle between Google and Oracle. Continue Reading
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Answer
31 Jul 2019
Oracle LEFT JOIN vs. LEFT OUTER JOIN: What's the difference?
Get an explanation of the different types of Oracle joins, including whether there's really a difference between the LEFT JOIN and LEFT OUTER JOIN syntax in PL/SQL. Continue Reading
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Answer
21 Nov 2013
Three tips for using Oracle insert syntax to insert multiple rows
If you're looking for insert syntax to insert multiple rows in Oracle, read these tips from three of our community members. Continue Reading
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Tip
16 Oct 2013
How to perform Oracle Flashback Transaction Queries
Read how Oracle Flashback Transaction Query can eliminate the need to use Log Miner to reconstruct database transactions. Continue Reading
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Answer
08 Feb 2012
Making Monday the start of the week in Oracle SQL
One reader asks how to set up a report in Oracle SQL so that Monday is the first day of the week. Continue Reading
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Answer
01 Feb 2010
When to use double quotes in Oracle column to avoid invalid identifier
Are you seeing an invalid identifier? Learn when to use double quotes in Oracle column names to avoid this in this tip from PL/SQL expert Dan Clamage. Continue Reading
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Feature
19 Aug 2009
SELECT statement syntax and examples
In this chapter, learn how to use the SELECT statement with SELECT statement examples, including the basics of the SELECT statement syntax. Continue Reading
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Answer
16 Apr 2009
How to concatenate rows into a single CLOB in PL/SQL
PL/SQL expert Dan Clamage explains how to concatenate rows into a single CLOB in PL/SQL. Continue Reading
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Answer
09 Apr 2009
Using the SQL GROUP BY clause for counting combinations
Read SQL expert Rudy Limeback's advice for counting combinations in a table with SQL's GROUP BY clause Continue Reading
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Answer
19 Feb 2009
How to sort an SQL UNION query with special ORDER BY sequence
SQL expert Rudy Limeback explains how to sort an SQL UNION query using a special ORDERY BY sequence. Continue Reading
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Answer
19 Nov 2008
Using an SQL SELECT statement from a non-existing table
SQL expert Rudy Limeback explains how to formulate a query using an SQL SELECT statement from a non-existing table. Continue Reading
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Answer
10 Nov 2008
Using LEFT OUTER JOIN query to get zero row counts in SQL
An SQL expert explains how using a LEFT OUTER JOIN query can retrieve zero row counts in SQL. Continue Reading
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Feature
17 Oct 2008
List the types of SQL subqueries
In this chapter, learn about the three broad divisions of a subquery in SQL: Single-row, multiple-row and correlated subqueries. Continue Reading
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Answer
15 Oct 2008
How to create an SQL CHECK constraint for two letters
SQL expert Rudy Limeback explains how to create a SQL CHECK constraint for two letters when trying to write a query to retrieve data from two tables. Continue Reading
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Answer
11 Sep 2008
How to return a zero in SQL instead of no row back for a select count
Want your row to return a zero instead of getting no row backs for some combinations when doing a select count in SQL? Find out how here. Continue Reading
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Answer
03 Jul 2008
Which normal form is used most?
SQL expert Rudy Limeback explains what normal form is used in most database projects. Continue Reading
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Answer
03 Jul 2008
Using BETWEEN with DATETIMEs in SQL
Expert Rudy Limeback is asked if SQL can be used to retrieve data between two dates, including the two dates. Continue Reading
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Answer
19 Jun 2008
SQL query for co-authored books
SQL expert Rudy Limeback gives advice for writing a query that involves a number of tables. Continue Reading
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Answer
20 May 2008
SQL for hourly totals for the last 48 hours
SQL expert Rudy Limeback explains to an Oracle user how to user asks how to generate datetimes or use left outer join to get hourly totals for the last 48 hours in SQL. Continue Reading
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Answer
20 May 2008
LEFT OUTER JOIN to a MIN/MAX row
An Oracle user asks SQL expert Rudy Limeback how to use a LEFT OUTER JOIN with a MIN/MAX condition. Continue Reading
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Answer
17 Apr 2008
How do I retrieve second transaction for each customer?
An Oracle user asks how to write a query to retrieve the second transaction for each customer. Continue Reading
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Answer
24 Mar 2008
SQL to round up to nearest thousand
SQL expert Rudy Limeback explains how to use the CEILING function. Continue Reading
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Answer
25 Jan 2008
Select from one table based on condition in another
SQL expert Rudy Limeback explains how to select from one table based on condition in another using an inner join in Oracle. Continue Reading
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Answer
16 Jan 2008
How to use DISTINCT on just one column
SQL expert Rudy Limeback explains how to use DISTINCT on just one column. Continue Reading
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Answer
01 Aug 2007
Integrity constraints and referential integrity
What is the difference between integrity constraints and referential integrity? Continue Reading
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Answer
20 Jul 2007
Use HAVING with CASE to count specific instances
I'm trying to construct a SELECT statement that will return people that have NO live courses running at the moment. Continue Reading
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Answer
20 Jul 2007
Difference between driving table and driver table in Oracle
I need to know the difference between the driving table and driver table in Oracle. Continue Reading
- Answer 17 Jul 2007
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Answer
15 Jun 2007
What is the difference between left outer join and (+) outer join?
What is the difference between left outer join and (+) outer join? Continue Reading
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Answer
07 Jun 2007
The MAX of two MAX values in SQL
Can I get the max of two columns into one column in SQL? Continue Reading
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Answer
31 May 2007
Obtaining COUNTs for males and females in one SQL query
For my table the gender column has only two values; F and M. I would like to do a count of both genders in one SQL query. Continue Reading
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Answer
24 May 2007
Using GROUP BY to collapse rows
Can I get the following with one select statement in SQL? Continue Reading
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Answer
18 May 2007
UPDATE only rows which match another table in SQL
I have a SQL query where I am trying to update a column in a table from data in another table. This works fine when I try to update all the records in the first table; however, Is it possible to update only the missing data? Continue Reading
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Answer
18 May 2007
SQL to calculate days to next status change
I would like to find out how long a particular customer order has been on hold in SQL. Continue Reading
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Answer
11 May 2007
Employees with the same first and last names in SQL
How do I SELECT a list of employees who have the same last and first name in SQL? Continue Reading
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Answer
26 Apr 2007
Columns in the SELECT not in the GROUP BY
I have an SQL query where I am using the SUM function with the GROUP BY clause. I need to select a couple more columns from the table without adding those columns in the GROUP BY clause. Continue Reading
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Answer
05 Apr 2007
LEFT OUTER JOIN without using LEFT OUTER JOIN
Can I get the same result as LEFT OUTER JOIN without using LEFT OUTER JOIN? Continue Reading
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Answer
02 Apr 2007
ORA-04082: NEW or OLD references not allowed in table level triggers
I am calling a stored procedure from a trigger. It shows the error: "ORA-04082: NEW or OLD references not allowed in table level triggers." Continue Reading
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Answer
22 Mar 2007
Add a column in a specific position in a table
I have created one table with three columns. I want to drop one column and add the column back to the same table in the same location. Continue Reading
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Answer
08 Mar 2007
Totals from a UNION query
I'm trying to retrieve a count of rows using a union, but for some reason I get two rows returned with different counts. Continue Reading
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Answer
22 Feb 2007
ORA-01702: a view is not appropriate here
I'm creating an index on a view using Oracle 9.2.0. I get the error ORA-01702 (a view is not appropriate here). Continue Reading
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Answer
17 Jan 2007
COUNT(*) or COUNT(1)
How do you specify difference between count(*) and count(1) in a select statement? Which is best to use and when? Continue Reading
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Answer
11 Jan 2007
Encountered the symbol "ELSE" when expecting one of the following
I am a beginner to Oracle. I am getting this error: "ORA-06550: line 21, column 1: PLS-00103: Encountered the symbol "ELSE" when expecting one of the following:" Continue Reading
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Answer
02 Jan 2007
GROUP BY multiple columns
My table structure is empid, category, col1, col2, amount. I would like to get the results as total of amounts for the col1 and col2 combinations, with a particular category. Continue Reading
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Answer
18 Dec 2006
Sorting a clob column
I'm trying to sort a column type asc as well as desc. I'm able to sort the clob column desc but not able to sort it asc. Can you please help me out? Continue Reading
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Answer
26 Oct 2006
Finding the highest COUNT in a GROUP BY query
I want to get the maximum of totalcontracts from the retrieved data using a select statement. Continue Reading
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Answer
06 Oct 2006
Foreign keys in a composite primary key
Is it possible to use one of the attributes of a composite primary key as a foreign key? Continue Reading
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Answer
01 Sep 2006
DISTINCT applies to all columns in the result
Could you tell me what are the effects of using the DISTINCT keyword before a group of different column names in a SELECT statement? Continue Reading
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Answer
14 Aug 2006
Difference between two dates in hours
How to calculate the difference between two dates in hours? Continue Reading
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Answer
14 Jul 2006
Using SQL to find the number of Sundays in a month
I want to find out how many Sundays come in any month in SQL. Continue Reading
- Answer 04 May 2006
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Answer
21 Apr 2006
ORDER BY a specified sequence
I'm trying to create an SQL query with the IN clause where I give the IDs to match. Now I want the order of these records to be the same as I give in the IN clause. But it's not happening. Continue Reading
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Answer
02 Dec 2005
Multiple rows with same value in one column
I'm doing a search from one table and my goal is to show only the rows with the same value in one of the columns. I am only interested in seeing the rows for all the emp_no that shows more than once. Continue Reading
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Answer
28 Oct 2005
DELETE WHERE NOT EXISTS
I have two tables, A1 and A2, and they both have a column called SSn. How will I delete a row from table A2 that doesn't exist on A1? Continue Reading
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Answer
19 Sep 2005
LEFT OUTER JOIN on more than two tables
Is it possible to perform LEFT OUTER JOIN in more than two tables? If possible, please give me details. Continue Reading
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Answer
16 Sep 2005
LEFT OUTER JOIN with ON condition or WHERE condition?
I would like your explanation of the difference between a LEFT OUTER JOIN ON condition and a WHERE condition. Continue Reading
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Answer
31 Aug 2005
Converting from CHAR to DATE datatype
As a time value, I used the CHAR datatype and need to convert to a DATE value while manipulating/computing. How do I use the DATE datatype instead? Continue Reading
- Answer 18 Apr 2005
- Answer 07 Jun 2004
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Tip
15 Mar 2004
Merging datasets with NULL values
A MERGE may appear to work properly, but it's important you check your target dataset to make sure it does. This tip explains why and how. Continue Reading
- Answer 18 Feb 2003
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- Answer 30 May 2001