SQL: 如何在具有特定 ID 的特定列中插入数据

Question

是否可以对单个 table 执行那种查询？

我读到它可以通过多个 table 来完成（通过从第二个中选择特定值插入第一个 table）

INSERT INTO Customers (CustomerName, Country)
SELECT SupplierName, Country FROM Suppliers
WHERE Country='Germany';

Answer 1

Is it possible to perform kind of that query on single table?

是的，有可能：

CREATE TABLE Customers(ID INT IDENTITY(1,1),
                       CustomerName VARCHAR(100), Country VARCHAR(100));

INSERT INTO Customers (CustomerName, Country)
VALUES ('John', 'USA'), ('Martin','Germany');

INSERT INTO Customers (CustomerName, Country)
SELECT CustomerName, Country 
FROM Customers
WHERE Country='Germany';

SELECT *
FROM Customers;

LiveDemo

请记住，需要 Table Spool 以避免 Halloween Effect

SQL: 如何在具有特定 ID 的特定列中插入数据

SQL: How to insert data in specific column with specific id as well

mysql

sql

sql-server

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