SQL Interview Question 面试的时候发现会问一些SQL的基本问题,在此总结一下。 ProgramInterview/SQL这个网站上的问题还比较全。 1. Join type INNER JOIN: Returns all rows when there is at least one match in BOTH tables LEFT JOIN: Return all r
1.表连接与差值计算：熟悉 `left join`、`right join`、`inner join` 和 `outer join` 的区别，并...
Left join:In MySQL, the use of the left join is done to return all the rows from the tables that are on the left side. There is another criterion that it should satisfy. That is the compatibility of the data in the right column with the data in the left column. Right join:In MySQL...
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SQL Job Interview Questions Table of Contents: What is SQL (Structured Query Language)? What is the SQL*Plus? What is NVL? What is a Character Functions? What is SET? What is a TTITLE & BTITLE? What is sql BREAK? What is sql JOIN? What is sql COMPUTE? What is SQL*Loader? What...
This question is a bit tough, as we'll have to use both the SUM function and the GROUP BY clause to aggregate orders by order_id. Here's how we do it: SELECT order_id, SUM(price) AS total_order_price FROM order_products INNER JOIN products ON order_products.product_id = products....
There was an interesting question once asked during an interview for SQL skills which looks like the below: "Which is the simplest type of join and which is the most generic type of join statement?" Though its evident that the answer to the former one is CROSS JOIN you might have...
32. What is Cross-Join? Cross join defines as Cartesian product where number of rows in the first table multiplied by number of rows in the second table. If suppose, WHERE clause is used in cross join then the query will work like an INNER JOIN....
14. Explain Self-Join with an Example The self-join meansjoining one table with itself. We can use the Self-Join on a table only if it has a column (we will call it A) that serves as the primary key and another column (that we will call Y) that stores values that can correspond...
1、join不同的表格求两列之间的差值，知道left，right，inner，outer join的区别 2、运用CASE根据已有的...