Skip to content

Tag: sql

Add hours/minutes to datetime

I’m having an issue on how to add the Offset to the EventDateTime. Is there a way to do this? I would convert it to a decimal number but cannot because 5:30 is not 5.3 hours, it’s 5 hours and 30 minutes. The data is shown below with the expected output. Please help if possible. Sample Data: Expect…

Finding last and second last date and corresponding values

Consider the following schema (fiddle): For each meter.id I need to find the latest reading date, value, and the value difference vs previous reading. For the sample data my output would look like this (plus some other columns from meters): meterid latest value delta value 1 20090403 399 99 2 20090403 288 44 …

MS SQL return single row case dataset without GROUP BY clause

I have a data set of ActivityDate which is a datetime field and EngineHours which is a decimal field. I want to return a single row of data that brings back the average number of EngineHours on each day of the week. The dataset is pretty big so the best performance is likely to be the most ideal, the script

IIF statement to filter Access Query with checkbox

I’m working on a search form based off a single table. I’m working primarily in the query design view. I’d like to have a checkbox on the form so if it is checked (true) it will only return records where the setID is Null. If unchecked (false) it will return all records regardless of if ther…

Relational Model – DBMS

I was going through some exercise problems to check my understanding of the relational model. According to my understanding, if we are given Album[mid] ⊆ Musician[mid], we can translate it into plain English as “Every album in the Database must have at least one musician”. If my understanding is r…

Postgresql reference a variable within statement

I come across this scenario frequently in sql and I have seen it done, but would like to summarize the case when/when not to reference a new variable within a statement. This doesn’t work – but this does – How can I implement scenario 1? Answer You can use a subquery.