Having the following schema: I am trying to a unique contraint to the column. But this runs into an error: I can understand that the column is already indexed because I have created the index by myself. But I want the column to be unique. Is there a way to do this? Answer This is indeed an undocumented limitation in
I have a table that looks something like and I would like to create all possible combinations with the sum of the prices, including the unique values to create something like what would be the quick and dirtiest way of accomplishing this? Answer Use three joins:
I am using the function below to generate a random number between 0 and 99999999999. However, I need to make sure that the returned number has never been used before in the same app. In .net I would create a while loop and keep looping until the returned value is not found in a table that stores previously used values.
So, I got in this situation: I create a table (let say model_a), in this table I have 2 cols (let say col1 and col2). I need a constraint that satisfy this reality: It’s not UNIQUE constraint, you can duplicate the first row. The only one time this constraint active is col1 is the same but col2 is different. Need
I am trying to find fact_order_id’s that have beverage only items. This would make the fact_order_id not include any food items. I have used 2 separate SQL Queries below. When I go back and check my work, I notice some fact_order_id’s in the output aren’t beverage only orders. Here are the 2 separate SQL Queries that give me the same
I have a table for storing coupons/discounts, and I want to use the coupon_code column as the primary key, which is a VARCHAR. My rationale is that, each coupon will have a unique code, and the only commands I will be running are SELECT … FROM … WHERE coupon_code=’..’ I won’t be doing any joins or indexing, and I don’t
Firstly, if it is relevant, I’m using MySQL, though I assume a solution would work across DB products. My problem is thus: I have a simple table with a single column. There are no constraints on the column. Within this column there is some simple data, e.g. I need to get the number/count of values that only appear once. From