A function performs some specified work, usually taking parameters as input. In terms of databases these may be specific to SQL or to the database vendor.

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34
votes
2answers
24k views

Create index if it does not exist

I am working on a function that allows me to add an index if it does not exist. I am running into the problem that I cannot get a list of indexes to compare to. Any thoughts? This is a similar issue ...
22
votes
2answers
1k views

Why does LEN() function badly underestimate cardinality in SQL Server 2014?

I have a table with a string column and a predicate that checks for rows with a certain length. In SQL Server 2014, I am seeing an estimate of 1 row regardless of the length I am checking for. This is ...
14
votes
1answer
5k views

SQL injection in Postgres functions vs prepared queries

In Postgres, are prepared queries and user defined functions equivalent as a mechanism for guarding against SQL injection? Are there particular advantages in one approach over the other?
14
votes
2answers
23k views

Is commit necessary after DML operation in Function/Procedure?

I wonder to know if it is necessary to write commit after insert/delete/update in function/procedure? Example: create or replace function test_fun return number is begin delete from a; return ...
13
votes
2answers
270 views

How to implement a Set based algorithm/UDF

I have an algorithm that I need to run against every row in a table with 800K rows and 38 columns. The algorithm is implemented in VBA and does a bunch of math using values from some columns to ...
10
votes
8answers
2k views

T-SQL : Is string a Palindrome?

I am a beginner in T-SQL. I want to decided whether an input string is a palindrome, with output =0 if it is not , output =1 if it is. I am still figuring out the syntax. I am not even getting an ...
10
votes
3answers
142 views

Theil-Sen estimator function in T-SQL

Does anyone have a Theil-Sen regression function written in T-SQL? I found one written in Perl, but I'm not able to recode it into SQL.
10
votes
1answer
13k views

How to use aes-encryption in PostgreSQL?

I tried aes-encryption by using following statement: SELECT encrypt('test', 'key', 'aes'); which worked, but I am not able to decrypt the value. I inserted it in a field of datatype bytea but I'm ...
10
votes
2answers
5k views

Is there a means to set the owner of all objects in a PostgreSQL database at the same time?

http://stackoverflow.com/questions/1348126/modify-owner-on-all-tables-simultaneously-in-postgresql describes some nifty ways to change table and other objects to a specific user, and it works ...
10
votes
1answer
1k views

Scalar function used in calculated column, what's the cleanest way to update the function?

I want to update a scalar function in our database. This function is used for several calculated columns in a key table so I get a dependency error if I try to update it. I can explicitly remove the ...
9
votes
1answer
17k views

Postgres function assign query results to multiple variables

I need to assign values to 2 variable as below in Postgres function. a := select col1 from tbl where ... b := select col2 from tbl where ... How can I assign 2 values to 2 variables in one line ...
9
votes
3answers
9k views

What does NVL stand for?

What does NVL stand for? I'm talking about the Oracle and Informix (perhaps some others too) function used to filter out non NULL values from query results (similar to COALESCE in other databases).
8
votes
3answers
764 views

Create function in central database or repeat in each database?

One of my developers has written a SQL function that works like the VB.Net function (LastIndexOf) and wants to publish it. My question is what would be the reason to put this in a central database ...
8
votes
1answer
1k views

Estimated versus actual query plan with function calls

I have this query on SQL server, a merge replication query: SELECT DISTINCT b.tablenick, b.rowguid, c.generation, sys.fn_MSgeneration_downloadonly ( c.generation, ...
8
votes
1answer
3k views

How does this syntax work? {fn CurDate()} or {fn Now()} etc

Recently I've been looking through some fairly old stored procedures that were written for SQL Server 2005, and I've noticed something that I don't understand. It appears to be some type of function ...
8
votes
3answers
3k views

Store a formula in a table and use the formula in a function

I have a PostgreSQL 9.1 database where part of it handles agent commissions. Each agent has his/her own formula of calculation how much commission they get. I have a function to generate the amount of ...
7
votes
3answers
6k views

How to pass a table type with an array field to a function in postgresql

i have a table called book CREATE TABLE book ( id smallint NOT NULL DEFAULT 0, bname text, btype text, bprices numeric(11,2)[], CONSTRAINT key PRIMARY KEY (id ) ) and a ...
7
votes
2answers
4k views

Why scalar valued functions need execute permission rather than select?

I am wondering why, for scalar valued function, that I have to grant the user to execute rather than just a select? meanwhile a table valued functions works just fine with only select permission or ...
7
votes
1answer
588 views

How to store and query products the price of which depends on a complex set of conditions?

I haven't decided on a database. I have expirience with MySQl and I'm intrigued by MongoDB. Let the products be packages of cable tv providers: { name: "Virgin TV", price: 20 }, { name: ...
7
votes
0answers
108 views

SQL Server - Handling localization of strings in nested non-deterministic view stacks

While profiling a database I came across a view that is referencing some non-deterministic functions that get accessed 1000-2500 times per minute for each connection in this application's pool. A ...
6
votes
5answers
1k views

Performance tuning a Great Circle distance calculation

I have a query that I am using to find locations that are within 1km of a known point. To do this, I am using the Spherical Law of Cosines formula with my latitude and longitudes. Currently, the ...
6
votes
3answers
2k views

Performance of Inline-TVF vs. Views

I have a database where i am using inline TVFs (table value functions) instead of views. For example, I might have two tables called [car model] and [car manufacturer] that I'm joining together ...
6
votes
2answers
1k views

T SQL Table Valued Function to Split varbinary(max) into 16byte GUIDs

I am trying to write a function which will split a varbinary(max) field into a table with 16 byte GUIDs, but am struggling. I haven't been able to find any examples or walkthroughs on how to do this ...
6
votes
2answers
312 views

User Defined Function (UDF) in master database

I have a function which is used in more than a dozen databases. I want this function to be accessible in all the databases by writing it only once, so I want to write the function in master database ...
6
votes
1answer
7k views

Transform all columns records to lowercase

I'm using PostgreSQL 9.1 and I have a users table with a login column. login names are case-sensitive, for example Bob, MikE, john. I would like to transform all these records into lowercase. ...
6
votes
2answers
1k views

Is this temp table behaviour documented?

Query Language (SQL) and PL/pgSQL functions treat temp tables differently: begin; create table foo(id) as values (1); select * from foo; /* id ---- 1 */ savepoint s; create function f() returns ...
5
votes
3answers
4k views

How can you save all user-defined functions to txt files on your local hard drive?

I am running SQL Server 2008 and need to back up the UDF scripts/queries that I have created. How can this be done in a timely manner? I tried right clicking on the folder icon where the UDF are saved ...
5
votes
4answers
179 views

Implicit conversion warning despite persisted computed column vs. performance hit from UDF in persisted computed column definition

I have a need for a computed column to resolve an implicit conversion problem. I have a column that is declared as a VARCHAR that should only ever store integers, but is occasionally populated in ...
5
votes
1answer
2k views

MySQL possibility to create global routines (stored procedures and/or functions)

Is it possible to somehow define globally available routines? It seems like every routine must be created in a scope of the database. When I tried to create a routine from console (without prior ...
5
votes
2answers
26k views

Granting Execute Permissions on Stored Procedures, Functions and Views

I am using a user which has read permission only. It basically has permission to Connect Execute However, it does not have execute permissions on Functions and Stored Procedures. In part of my ...
5
votes
1answer
164 views

How to better use CLR Function from performance point of view (repeat inside each DB or have general function)?

I asked a question about validation of XML using XSD schema inside SQL Server 2012 (see link). I understand (as I suspected) that I need to use CLR Function. The function will get XSD schema text and ...
5
votes
2answers
914 views

Optimize queries from MySQL SP/Triggers/Functions

I have to investigate a MySQL Production server,While investigating I found a DELETE query in "SHOW PROCESSLIST" which was taking more than 400 second in preparing state, I tried to find the query in ...
5
votes
2answers
4k views

Postgresql function to create table

I want to create a function in order to create a table with a specific structure pasing part of the name of the table as an argument so the name of the table is t_ . Similar to this: CREATE OR ...
5
votes
2answers
3k views

Call multiple functions from trigger?

I run PostgreSQL-9.2.4 Is it possible to call 2 functions from a trigger? Let's say I have two functions for two different tables to be executed if following trigger fires: Trigger: CREATE TRIGGER ...
5
votes
2answers
3k views

Why do I get leading zeros when converting from decimal to char in a db2 query?

I have a column named length defined as: TYPE_NAME: DECIMAL DATA_TYPE: 3 COLUMN_SIZE: 9 BUFFER_LENGTH: 11 DECIMAL_DIGITS: 5 NUM_PREC_RADIX: 10 When I run the following select: select ...
5
votes
1answer
3k views

Oracle extract slow function call from a WHERE clause

I have an oracle table in which dates are stored as the number of minutes since a specific date. It looks something like this: CREATE TABLE MY_TABLE ( SOMETHING NUMBER(15,1) NOT NULL, ...
5
votes
1answer
809 views

Is it possible to wrap aggregate functions in Postgres?

Postgres' string_agg(expr, delimiter) function is great. But I would like to have a version that takes a single argument -- the field to aggregate -- and assumes a delimiter of ', ' since that is ...
5
votes
2answers
327 views

How do I create a user-defined aggregate function in MySQL (redux)?

OK, I'm probably going to get banned for asking the same question a second time, but I'm an incredible newbie here and I was told I don't have enough of a reputation to comment on the original ...
5
votes
2answers
852 views

SQL Server SMO and PowerShell formatting

I have probably been looking at this for too long to figure this out... What is the easiest way I could get this exported to a CSV format? Would it be better to dump this to a table in a database ...
4
votes
1answer
620 views

Getting error “must declare the scalar variable” in SQL function even though it is declared

I am altering function like: ALTER FUNCTION [dbo].[fn_CalculateListing](@Listing TypeListingDatePrice READONLY) RETURNS TypePreviousListingResult AS BEGIN DECLARE @tbl_ListingDateDetails ...
4
votes
2answers
239 views

Custom Postgres function not working

I wrote this function that is supposed to iterate through a text array and convert each element (which is a typecasted integer) to hex, append to a text variable, then return the hex. However, I get ...
4
votes
1answer
1k views

Running functions in parallel

This is for SQL Server 2012. We have some import processes for FTP files that are picked up and read into a staging table, from there we massage/check the data before moving into production. One of ...
4
votes
1answer
15k views

Invalid use of a side-effecting operator 'INSERT' within a function - Multiple Inserts in Function

If this is not the right forum please let me know and move it for me. I've just got a bunch of inserts like this toward the end of my scalar function: INSERT INTO [Raptor].[dbo].[UserRole] ...
4
votes
1answer
839 views

Why does it take a long time to drop a function based index in Oracle?

I have a function based index that takes 25 minutes to create on a table of 94 Million rows. When I drop the index, it takes 18 minutes. Why does it take so long? I would have thought the drop would ...
4
votes
1answer
3k views

Use NOLOCK hint when calling table valued function

Suppose the following function: CREATE FUNCTION [dbo].[ufnTest]() RETURNS TABLE AS RETURN SELECT 1 AS Nr My actual function will select actual data from many different tables. I (mostly) understand ...
4
votes
3answers
7k views

how to create backup for stored procedure,trigger and functions of a database in sql server 2008?

I'm having 2 databases in 2 different servers(.246 and .252). I need to create backup for all stored procedures, triggers and function from 252 server and restore it in 246 server.database name in ...
4
votes
1answer
590 views

Calculating Average Excluding Outliers

I'm looking for a SQL Server function that will let me take an average, excluding outliers. Basically something where: 1, 2, 1, 2, 7 Would average out to 1.5. I'm going to implement this in a ...
4
votes
2answers
2k views

Add function parameter to SQL query WHERE clause

I have a web application in java and it uses a query. I don't want to write the query into Java, so I made a function: CREATE OR REPLACE FUNCTION testFunc(inputs text) RETURNS TABLE(...) AS $$ ...
4
votes
1answer
456 views

How Can the Same Query in Two Nearly Identical Instances Generate Two Different Execution Plans?

Server A and Server B have identical hardware and instance configurations (A is Production, B is QA). B's DBs were restored from A's backups from one week ago. I was provided this query by the ...
4
votes
1answer
4k views

Function/procedure to use dblink to fetch remote data and insert to multiple local tables

Am trying to fetch data from remote db and insert into three local tables. Currently I have a query which is successfully getting the data into one table. But now I was thinking of creating a ...