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How to know if a query is pulling the same record multiple times?
I know that the query is pulling the same record multiple times because; – when I remove the GROUP BY term, I get several records that are exactley the same. – There are however, only one instance of these records in the corresponding tables.
Why is MY SQL query returning Duplicate results?
I recently reviewed a SQL query that was returning duplicate results. Since I expected, and needed, a single result from the query this was a problem. Here’s an explanation of why this bug occurred, and several different ways it can be resolved.
What to do if SQL query is called twice?
Put a break point at addNewComment and if it is being called twice look at the stack traces to see where it is being called from on both occasions. Maybe you have an event being called twice for example. This can happen in ASP.NET if you both have auto wiring of events enabled and have wired the event up explicitly.
How can I get rid of duplicates in my query?
My first attempt to remove the duplicates was to add the DISTINCT keyword to my query, but that didn’t fix the problem – I was still seeing duplicates. As I was looking at the result set more closely I realized that the problem was in how the query was structured and the columns that it was returning in the results.
What’s the problem with selecting the same column twice?
The problem with your original query was that the condition in the subquery did not depend on the specific record. The subquery returned the name of every employee who is the boss of someone else. Please note that this solution usually has a worse performance than the join because it has to execute the subquery for every item.
What’s the best way to pull data in MS Access?
Rather than try to pull everything into a single large query straight away, it’s best to create simple queries for each of those goals and make sure we get the proper data in each case. From what you explain, each individual bar is recorded in the BarStock table.
Which is worse a subquery or a join?
The subquery returned the name of every employee who is the boss of someone else. Please note that this solution usually has a worse performance than the join because it has to execute the subquery for every item. Although the result is equivalent to that of the join many optimizers do not realize this because they do not touch subqueries.