I&#39;ve never known there to be a difference.  The [Oracle documentation][1] implies that they are synonyms:

&gt; The function body begins with the keyword `IS` (or `AS`) and ends with the keyword END followed by an optional function name.


  [1]: http://download.oracle.com/docs/cd/B10501_01/appdev.920/a96624/08_subs.htm

Same as DISTINCT and UNIQUE in select statements.
i.e, there is no material difference between &#39;IS&#39; and &#39;AS&#39;.
Backwards compatibility and meeting standards

I just want to know if C supports over loading?
As we use system functions like printf with different no of arguments.
Help me out


Does C support overloading?

I am wondering if maybe ReSharper is able to run through every class and remove unused usings?  I looked but I don&#39;t see an option like this in R# 4.5.  Has anyone seen this in Resharper outside of just being able to remove usings in a single class?

Remove unused Usings across entire assembly

I have been trying to find out what the difference is between the `IS` and `AS` keywords in PL/SQL when creating an Oracle function or procedure. 

I have searched and have been unable to find any information on this. Does anyone know the difference?

IS vs AS keywords for PL/SQL Oracle Function or Procedure Creation

<p>I have been trying to find out what the difference is between the <code>IS</code> and <code>AS</code> keywords in PL/SQL when creating an Oracle function or procedure.</p>
<p>I have searched and have been unable to find any information on this. Does anyone know the difference?</p>


You often see database fields set to have a magnitude of 255 characters, what is the traditional / historic reason why? I assume it&#39;s something to do with paging / memory limits, and performance but the distinction between 255 and 256 has always confused me.

    varchar(255)

Considering this is a capacity or magnitude, *not an indexer*, **why is 255 preferred over 256?** Is a byte reserved for some purpose (terminator or null or something)?

Presumably varchar(0) is a nonsense (has zero capacity)? In which case 2^8 of space should be 256 surely?

Are there other magnitudes that provide performance benefits? For example is varchar(512) less performant than varchar(511) or varchar(510)?

Is this value the same for all relations databases, old and new?

**disclaimer** - I&#39;m a developer not a DBA, I use field sizes and types that suit my business logic where that is known, but I&#39;d like to know the *historic* reason for this preference, even if it&#39;s no longer relevant (but even more if it still is relevant).

Edit:
-----

Thanks for the answers, there seems to be some concensus that a byte is used to store size, but this doesn&#39;t settle the matter definitively in my mind.

If the meta data (string length) is stored in the same contiguous memory/disk, it makes some sense. 1 byte of metadata and 255 bytes of string data, would suit each other very nicely, and fit into 256 contiguous bytes of storage, which presumably is neat and tidy.

But...If the metadata (string length) is stored separately from the actual string data (in a master table perhaps), then to constrain the length of string&#39;s data by one byte, just because it&#39;s easier to store only a 1 byte integer of metadata seems a bit odd.

In both cases, it would seem to be a subtlety that probably depends on the DB implementation. The practice of using 255 seems pretty widespread, so someone somewhere must have argued a good case for it in the beginning, can anyone remember what that case was/is? Programmers won&#39;t adopt any new practice without a reason, and this must have been new once.

Why historically do people use 255 not 256 for database field magnitudes?

I am new to MySQL. I would like to copy the content of one table to another table within the same database. Basically, I would like to insert to a table from another table. Is there easy way of doing this?



In MySQL, how to copy the content of one table to another table within the same database?

I&#39;m in the process of creating a table and it made me wonder.

If I store, say cars that has a make (fx BMW, Audi ect.), will it make any difference on the query speed if I store the make as an int or varchar.

So is

    SELECT * FROM table WHERE make = 5 AND ...;

Faster/slower than

    SELECT * FROM table WHERE make = &#39;audi&#39; AND ...;

or will the speed be more or less the same?

SQL SELECT speed int vs varchar

I&#39;m faced with the following and I&#39;m not sure what&#39;s best practice.

Consider the following table (which will get large):

id PK | giver_id FK | recipient_id FK | date

I&#39;m using InnoDB and from what I understand, it creates indices automatically for the two foreign key columns. However, I&#39;ll also be doing lots of queries where I need to match a particular combination of: 

`SELECT...WHERE giver_id = x AND recipient_id = t`.

Each such combination will be unique in the table.

Is there any benefit from adding an two-column index over these columns, or would the two individual indexes in theory be sufficient / the same?

Two single-column indexes vs one two-column index in MySQL?

I accidentally deleted some huge number of rows from a table...

How can I roll it back?

I executed the query using [PuTTY][1].

I&#39;ll be grateful if any of you can guide me safely out of this...

  [1]: http://en.wikipedia.org/wiki/PuTTY


How can I roll back my last delete command in MySQL?

I have &quot;read only&quot; access to a few tables in an Oracle database. I need to get schema information on some of the columns. I&#39;d like to use something analogous to MS SQL&#39;s `sp_help`. 

I see the table I&#39;m interested in listed in this query:

    SELECT * FROM ALL_TABLES

When I run this query, Oracle tells me &quot;table not found in schema&quot;, and yes the parameters are correct.

    SELECT 
    DBMS_METADATA.GET_DDL(&#39;TABLE&#39;, &#39;ITEM_COMMIT_AGG&#39;, &#39;INTAMPS&#39;) AS DDL
    FROM DUAL;

After using my Oracle universal translator 9000 I&#39;ve surmised this doesn&#39;t work because I don&#39;t have sufficient privileges. Given my constraints how can I get the datatype and data length of a column on a table I have read access to with a PL-SQL statement?

How do I get column datatype in Oracle with PL-SQL with low privileges?

Is there a way of finding the name of the server an Oracle database is hosted on?

Find the server name for an Oracle database

I am using oracle database. i want to execute one query to check the data between two dates.


    NAME               START_DATE    
    -------------    ------------- 
    Small Widget       15-JAN-10 04.25.32.000000 PM      
    Product 1          17-JAN-10 04.31.32.000000 PM  

  

    select * from &lt;TABLENAME&gt; where start_date  
    BETWEEN &#39;15-JAN-10&#39; AND &#39;17-JAN-10&#39;

But I dont get any results from above query. I think I have to use &quot;like&quot; and &quot;%&quot;. But I dont know where to use them. Please throw some lights on this. 

thanks in advance.

Oracle date &quot;Between&quot; Query

I&#39;m getting the same results from 

    select length(column_name) from table

as

`select dbms_lob.getlength(column_name) from table` 

However, the answers to
&lt;a href=&quot;https://stackoverflow.com/questions/840966/what-is-an-elegant-way-to-return-a-readable-file-size-of-a-file-stored-in-an-or&quot;&gt;this question&lt;/a&gt; seem to favor using `dbms_lob.getlength()`.  
  
Is there any benefit to using `dbms_lob.getlength()`? 

If it changes the answer, I know all of the blobs are .bmp images (never worked with blobs before).

dbms_lob.getlength() vs. length() to find blob size in oracle

I&#39;m trying to retrieve records from table by knowing the date in column contains date and time.

Suppose I have table called `t1` which contains only two column `name` and `date` respectively.

The data stored in column date like this `8/3/2010 12:34:20 PM`.

I want to retrieve this record by this query for example (note I don&#39;t put the time):

    Select * From t1 Where date=&quot;8/3/2010&quot;

This query give me nothing ! 

How can I retrieve `date` by knowing only `date` without the time?

Select from table by knowing only date without time (ORACLE)

I have a database which has a NOT NULL constraint on a field, and I want to remove this constraint.  The complicating factor is that this constraint has a system-defined name, and that constraint&#39;s name differs between the production server, integration server, and the various developer databases.  Our current process is to check in change scripts, and an automated task executes the appropriate queries through sqlplus against the target database, so I&#39;d prefer a solution that could just be sent straight into sqlplus.

On my own database, the SQL to drop this would be:

    alter table MYTABLE drop constraint SYS_C0044566

I can see the constraint when I query the `all_constraints` view:

    select * from all_constraints where table_name = &#39;MYTABLE&#39;

but I am not sure how to work with the `SEARCH_CONDITION`&#39;s `LONG` data type or how best to dynamically delete the looked-up constraint even after I know its name.

So, how can I create a change script that can drop this constraint based on what it is, rather than what its name is?

----
EDIT:
@Allan&#39;s answer is a good one, but I am concerned (in my lack of Oracle expertise) that it may not be universally true that any constraint that might have a system-generated name will have associated with it a way to remove the constraint without having to know its name.  Is it true that there will always be a way to avoid having to know a system-named constraint&#39;s name when logically dropping that constraint?

How can I drop a &quot;not null&quot; constraint in Oracle when I don&#39;t know the name of the constraint?

Using the DUAL table, how can I get a list of numbers from 1 to 100?

SQL to generate a list of numbers from 1 to 100

In SQL I (sadly) often have to use &quot;`LIKE`&quot; conditions due to databases that violate nearly every rule of normalization. I can&#39;t change that right now. But that&#39;s irrelevant to the question.

Further, I often use conditions like `WHERE something in (1,1,2,3,5,8,13,21)` for better readability and flexibility of my SQL statements.

Is there any possible way to combine these two things without writing complicated sub-selects?

I want something as easy as `WHERE something LIKE (&#39;bla%&#39;, &#39;%foo%&#39;, &#39;batz%&#39;)` instead of this:

    WHERE something LIKE &#39;bla%&#39;
    OR something LIKE &#39;%foo%&#39;
    OR something LIKE &#39;batz%&#39;

I&#39;m working with SQl Server and Oracle here but I&#39;m interested if this is possible in any RDBMS at all.

Is there a combination of &quot;LIKE&quot; and &quot;IN&quot; in SQL?

In SQL Server we can type `IsNull()` to determine if a field is null.  Is there an equivalent function in PL/SQL?

Content Type	Original Author	Original Content on Stackoverflow
Question	Joel Cunningham	View Question on Stackoverflow
Solution 1 - Sql	OMG Ponies	View Answer on Stackoverflow
Solution 2 - Sql	pj.	View Answer on Stackoverflow

IS vs AS keywords for PL/SQL Oracle Function or Procedure Creation

Sql Problem Overview

Sql Solutions

Solution 1 - Sql

Solution 2 - Sql

Remove unused Usings across entire assembly

Does C support overloading?

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