I’m writing a webpage to interactively filter results based on filter criteria as it is specified by the user. I only want to return from SQL the TOP 20 rows but I want to know how many rows met the criteria (Count). I want to be able to tell the user: “here are the top 20 rows matching your criteria,
Foreign Key Used in Composite Primary Key
Is it possible to use a composite foreign key as a piece of a table’s composite primary key? For instance, let’s say I have two tables: … and then in a second table, I would like to reference the foreign key in the second table’s primary key: Is there any way that I can do that? Yes, it might be
Split Result from SQL Query
For example this SQL statement returns 1k rows SELECT * FROM tableName WHERE someCondition my question is: is it possible by using WHERE 1) Split Resultset to the 10 partial resultsets, then 1st….
Can a foreign key be NULL and/or duplicate?
Please clarify two things for me: Can a Foreign key be NULL? Can a Foreign key be duplicate? As fair as I know, NULL shouldn’t be used in foreign keys, but in some application of mine I’m able to …
Get number of values that only appear once in a column
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
How to get max value of a column using Entity Framework?
To get maximum value of a column that contains integer, I can use the following T-SQL comand SELECT MAX(expression ) FROM tables WHERE predicates; Is it possible to obtain the same result with …
Some sort of “different auto-increment indexes” per a primary key values
I have got a table which has an id (primary key with auto increment), uid (key refering to users id for example) and something else which for my question won’t matter. I want to make, lets call it, different auto-increment keys on id for each uid entry. So, I will add an entry with uid 10, and the id field
Doctrine 2 Query Builder abs Function
This Work: This Don’t Work: The Error: Syntax Error] line 0, col 118: Error: Expected end of string, got ‘(‘ The native doctrine function abs work only on a select part of statment and don’t work on order by part. Obs: 1-) Im avoiding to use NativeQuery. 2-) u.code is a varchar fild on mysql and need to be varchar
How do I add a custom CHECK constraint on a MySQL table?
I am having trouble with this table I want to have a foreign key constraint, and that works. Then, I also want to add a constraint to the attribute status so it can only take the values ‘a’, ‘d’ and ‘u’. It is not possible for me to set the field as Enum or set. Can anyone tell me why
Bulk load data conversion error (truncation)
I am getting this error Bulk load data conversion error (truncation) for row 1, column 12 (is_download) here is the csv…it only has one row 30,Bill,Worthy,sales,,709888499,bat@bat.com,,”Im a a …