MySQL 插入数据

[xgqfrms]

MySQL 插入数据

INSERT INTO SQL语法：

INSERT INTO table_name ( field1, field2,...fieldN )
                       VALUES
                       ( value1, value2,...valueN );

如果数据是字符型，必须使用单引号或者双引号，如："value"。

https://www.runoob.com/mysql/mysql-insert-query.html

[xgqfrms]

demo

https://github.com/xgqfrms/mysql/issues/8

INSERT INTO Employees (employee_id, name)
VALUES (1, "MySQL");

INSERT INTO Employees (employee_id, name)
VALUES (2, "SQL");

INSERT INTO Employees (employee_id, name)
VALUES (3,  NULL);

INSERT INTO Salaries (employee_id, salary)
VALUES (1,  100);

INSERT INTO Salaries (employee_id, salary)
VALUES (2,  200);

INSERT INTO Salaries (employee_id, salary)
VALUES (3,  NULL);

[xgqfrms]

sollution

SELECT employee_id 
FROM (
  SELECT employee_id FROM Employees
  UNION ALL
  SELECT employee_id FROM Salaries
) AS T
GROUP BY employee_id
HAVING COUNT(employee_id) = 1
ORDER BY employee_id;

test

SELECT employee_id 
FROM (
  SELECT employee_id FROM Employees
  UNION ALL
  SELECT employee_id FROM Salaries
) AS T
GROUP BY employee_id
ORDER BY employee_id;

SELECT employee_id 
FROM (
  SELECT employee_id FROM Employees
  UNION ALL
  SELECT employee_id FROM Salaries
) AS T
HAVING COUNT(employee_id) = 1
ORDER BY employee_id;

SELECT employee_id 
FROM (
  SELECT employee_id FROM Employees
  UNION ALL
  SELECT employee_id FROM Salaries
) AS T
ORDER BY employee_id;

[xgqfrms]

SELECT *
FROM (
  SELECT employee_id FROM Employees
  UNION ALL
  SELECT employee_id FROM Salaries
) AS t;