I usually use Google BigQuery only for simple aggregate SQL, but there are many other useful functions besides aggregate SQL. However, since I don't use it often and when I do try to use it, I start by looking for a manual, so I'll put tog…

I usually use Google BigQuery only for simple aggregate SQL, but there are many other useful functions besides aggregate SQL. However, since I don't use it often and when I do try to use it, I start by looking for a manual, so I'm going to…

I usually use Google BigQuery only for simple aggregate SQL, but there are many other useful functions besides aggregate SQL. However, since I don't use it often and when I do try to use it, I start by looking for a manual, so I'll put tog…

I usually use Google BigQuery only for simple aggregate SQL, but there are many other useful functions besides aggregate SQL. However, since I don't use it often and when I do try to use it, I start by looking for a manual, so I'll put tog…

I usually use Google BigQuery only for simple aggregate SQL, but there are many other useful functions besides aggregate SQL. However, since I don't use it often and when I do try to use it, I start by looking for a manual, so I'll put tog…

I usually use SQL, but when I am working with array data in JavaScript, I sometimes wish I could write queries in SQL for JavaScript arrays. On the other hand, C# has a language called LINQ that can process arrays with SQL-like queries. Th…

When I started learning SQL, the window functions (analytic functions) were the most difficult to understand. Although you do not need to use the window function when using a database simply as a place to store and retrieve data, it is a v…

This is a memo on how to use SQLite with JavaScript. We did not elaborate too much, but focused on the minimum necessary functions. I will not go into the usage of SQLite itself, but please refer to this way (direction close to the speaker…

SQL Server data is read by BI tools to create graphs. In that case, we did not want to use a user with write permission because the data would only be read and various people would create graphs, so we created a read-only user for sharing.…

I did not know that SQL Server was the first time to use Azure SQL Database, but in SQL Server, queries across databases can be easily written by specifying the database, as shown below. SELECT * FROM [<db_name>].dbo.test_table However, when I try </db_name>…

To aggregate data by month/week, first find the beginning date of the month/week of the date and GROUP by that beginning date. If the DATE_TRUNC() function can be used to get the head date, such as Google BigQuery, you can aggregate the da…

For example, "In a user's event log, I want to extract the last event the user performed." Sometimes you want to retrieve the last record of data divided by groups. The window function can be used to obtain the following WITH tbl AS ( SELE…

BigQuery can handle huge amounts of data, but you don't have to worry about the infrastructure at all (really, at all), and it's fast and cheap, It is tempting to put all your data into BigQuery and process it all with BigQuery. That's why…

I wanted a calendar table in SQL Server (Azure SQL Database), so here is a memo on how to create one. I googled, and it seems to be created by creating a table with "WITH" and then making a recursive call from "UNION ALL" in the table defi…

When aggregating data that jumps around by date, you may want a calendar table. You can create a calendar table in Google BigQuery with the following GENERATE_DATE_ARRAY()" creates a calendar array, and "UNNEST()" expands the array to rows…