From this post How to use ROW_NUMBER in the following procedure? There are two versions of answers where one uses a sub-query and the other uses a CTE to solve the same problem. Now then, what is the advantage of using a CTE (Common Table Expression) over a ‘sub-query`(thus, more readable what the query…
Tag: sql
How to combine date from one field with time from another field – MS SQL Server
In an extract I am dealing with, I have 2 datetime columns. One column stores the dates and another the times as shown. How can I query the table to combine these two fields into 1 column of type datetime? Dates Times Answer You can simply add the two. if the Time part of your Date column is always zero
Creating table names that are reserved words/keywords in MS SQL Server [closed]
Is it ok to name my database tables that are already keywords? For my case, I am trying to name the table that will hold my users. I’ve named it User but it is showing up as pink in SQL Server …
Cannot simply use PostgreSQL table name (“relation does not exist”)
I’m trying to run the following PHP script to do a simple database query: This produces the following error: Query failed: ERROR: relation “sf_bands” does not exist In all the examples I can find where someone gets an error stating the relation does not exist, it’s because they use upp…
How to determine the number of days in a month in SQL Server?
I need to determine the number of days in a month for a given date in SQL Server. Is there a built-in function? If not, what should I use as the user-defined function?
How do I UPDATE a row in a table or INSERT it if it doesn’t exist?
I have the following table of counters: I would like to increment one of the counters, or set it to zero if the corresponding row doesn’t exist yet. Is there a way to do this without concurrency issues in standard SQL? The operation is sometimes part of a transaction, sometimes separate. The SQL must ru…
MySQL query to extract first word from a field
I would like to run a query that returns the first word only from a particular field, this field has multiple words separated by spaces, I assume I may need to carry out some regex work to accomplish this? I know how to do this using a few ways in PHP but this would best be carried out on the
How can I find duplicate entries and delete the oldest ones in SQL?
I’ve got a table that has rows that are unique except for one value in one column (let’s call it ‘Name’). Another column is ‘Date’ which is the date it was added to the database. What I want to do is find the duplicate values in ‘Name’, and then delete the ones …
How to execute an .SQL script file using c#
I’m sure this question has been answered already, however I was unable to find an answer using the search tool. Using c# I’d like to run a .sql file. The sql file contains multiple sql statements, some of which are broken over multiple lines. I tried reading in the file and tried executing the fil…
How do I spool to a CSV formatted file using SQLPLUS?
I want to extract some queries to a CSV output format. Unfortunately, I can’t use any fancy SQL client or any language to do it. I must use SQLPLUS. How do I do it?