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Counting null and non-null values in a single query
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This works for Oracle and SQL Server (you might be able to get it to work on another RDBMS):
select sum(case when a is null then 1 else 0 end) count_nulls
, count(a) count_not_nulls
from us;
Or:
select count(*) - count(a), count(a) from us...
Only initializers, entity members, and entity navigation properties are supported
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Entity is trying to convert your Paid property to SQL and can't because it's not part of the table schema.
What you can do is let Entity query the table with no Paid filter and then filter out the not Paid ones.
public ActionResult Index()
{
var debts = storeDB.Orders...
How to store arrays in MySQL?
I have two tables in MySQL. Table Person has the following columns:
7 Answers
7
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Convert Linq Query Result to Dictionary
I want to add some rows to a database using Linq to SQL, but I want to make a "custom check" before adding the rows to know if I must add, replace or ignore the incomming rows.
I'd like to keep the trafic between the client and the DB server as low as possible and minimize the number of queries.
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What are best practices for multi-language database design? [closed]
...lly you should develop your own database access class, that pre-parses the SQL that contains your special localization markup and converts it to the actual SQL you will need to send to the database.
Using that system might look something like this:
db.setLocale("en");
db.query("SELECT p.price, _(p...
Update multiple rows in same query using PostgreSQL
I'm looking to update multiple rows in PostgreSQL in one statement. Is there a way to do something like the following?
6 An...
CHECK constraint in MySQL is not working
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MySQL 8.0.16 is the first version that supports CHECK constraints.
Read https://dev.mysql.com/doc/refman/8.0/en/create-table-check-constraints.html
If you use MySQL 8.0.15 or earlier, the MySQL Reference Manual says:
The...
Convert MySQL to SQlite [closed]
Is it possible to convert from MySQL to SQLite with a free tool on windows?
15 Answers
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How to create a multi-tenant database with shared table structures?
Our software currently runs on MySQL. The data of all tenants is stored in the same schema. Since we are using Ruby on Rails we can easily determine which data belongs to which tenant. However there are some companies of course who fear that their data might be compromised, so we are evaluating othe...
How to execute a stored procedure within C# program
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using (var conn = new SqlConnection(connectionString))
using (var command = new SqlCommand("ProcedureName", conn) {
CommandType = CommandType.StoredProcedure }) {
conn.Open();
command.ExecuteNonQuery();
}
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