在数据存在性判断中，建议使用COUNT(*)，其性能优于COUNT(主键)和COUNT(非主键列)，且符合SQL标准，清晰高效。

This is the second blog in the series where I talk about INSTANT ADD/DROP columns feature introduced in MySQL 8.0. After the introductory Blog, this blog aims to provide more design details.

This blog gives details of the new feature introduced in MySQL 8.0.29 using which column(s) can be added/dropped to/from a table with ALGORITHM=INSTANT.

可以使用“SELECT * FROM mytable ORDER BY column + 0”来将column视为INT，也可以将column同时当作INT和VARCHAR处理。

前言SQL Server 支持 JSON, 以前写过一篇介绍 SQL Server – Work with JSON. 但 EF Core 一直没有支持。直到 EF Core 7.0 才支持。EF Core 7 包含对 JSON 列的提供程序无关的支持，以及 SQL Server 的实现。此支持允许将从 .NET 类型生成的聚合映射到 JSON 文档。可以在聚合上使用普通的 LINQ 查询，这些...

按列格式化输出文件 阅读更多

You can’t make an SSIS Derived Column useful without expressions. So, how do you write one? This article will give you tips on using derived column transformation. Here’s what we are going to...

I have a file where each line has several comma-separated items. I want to sort the lines, based on a certain column. How do we do it inside Vim/Nvim?

Flutter 线性布局：Column 和 Row 的常用属性

Flutter 线性布局：Column 和 Row 的常用属性