
database - How to select unique records by SQL - Stack Overflow
When I perform SELECT * FROM table I got results like below: 1 item1 data1 2 item1 data2 3 item2 data3 4 item3 data4 As you can see, there are dup records from column2 (item1 are dupped). So …
Get unique values from a list in python - Stack Overflow
Oct 15, 2012 · I want to get the unique values from the following list:
df.unique () on whole DataFrame based on a column
Apr 3, 2017 · uniqueId = df["Id"].unique() I get a list of unique IDs. How can I apply this filtering on the whole DataFrame such that it keeps the structure but that the duplicates (based on "Id") are removed?
How to add unique field validation in nest js with class-validator
Mar 7, 2023 · How to do validation with database like unique filed validation in nest JS using the class validator? I created a custom validation class and tried it. But userService was undefined when I …
Entity Framework Core add unique constraint code-first
The OP is asking about whether it is possible to add an Attribute to an Entity class for a Unique Key. The short answer is that it IS possible, but not an out-of-the-box feature from the EF Core Team. If you'd …
Get all unique values in a JavaScript array (remove duplicates)
I have an array of numbers that I need to make sure are unique. I found the code snippet below on the Internet, and it works great until the array has a zero in it. I found this other script here on
sql - How to select only the first rows for each unique value of a ...
In the table, one customer like John Smith can have multiple addresses. I need the SELECT query for this table to return only first row found where there are duplicates in 'CName'. For this table it should …
Difference between primary key and unique key - Stack Overflow
Mar 5, 2012 · Unique Key (UK): It's a column or a group of columns that can identify a uniqueness in a row. Primary Key (PK): It's also a column or group of columns that can identify a uniqueness in a …
SQL to find the number of distinct values in a column
Apr 5, 2019 · SELECT DISTINCT my_col, count(*) OVER (PARTITION BY my_col ORDER BY my_col) AS num_rows FROM my_tbl Using this OVER based approach is of course optional. In the above …
How can I create unique IDs with JavaScript? - Stack Overflow
Mar 19, 2019 · I have a form where a user can add multiple select boxes for multiple cities. The problem is that each newly generated select box needs to have a unique id. Can this be done in JavaScript? …