SQL Practice - July 3,18 One day off for yesterday because of overtime work. Again, two questions for today. Question 1:Consecutive Numbers Source: Leetcode Write a SQL query to find all numbers that appear at least three times consecutively. For example, given the above Logs table, 1 is...
Here are 5 practice interview questions to get you started.New: Sign up for a free SQL mini-course Make sure you're prepared for the interview that could change your career. Sign up to receive five free must-learn lessons in preparation for your SQL interview. Start preparing today! First...
The use of comparison operators like <,> or = can be done in a subquery. These kinds ofSQL Interview Questionsare a bit difficult to understand and answer accordingly. There are a lot ofSQL Interview Questionsapart from this, which the candidates must practice qualifying for the interview. Fo...
From the following tables write a SQL query to list all salespersons along with customer name, city, grade, order number, date, and amount. Condition for selecting list of salesmen : 1. Salesmen who works for one or more customer or, 2. Salesmen who not yet join under any customer, Con...
A The BPA recommendation to schema-qualify table and view references doesn’t really apply on SQL Server™ 2005, as user-schema separation has fixed the problem that required this practice on earlier versions of SQL Server. Schema-qualification was required to enable query plan reuse by differen...
When we execute a query and use theWHEREkeyword on a column that does not have an index, then the SQL Server has to do a full-table scan and check every row to find matches. This is a bad practice because it can be unpredictable in terms of execution time. Therefore this process may...
SQL quiz questions. For example: “What is a primary key?” Or “List the different types of JOINs!” That’s a stupid type of SQL tech assessment — as it focuses on theory and not on practice. Still, some companies… you know. Take-home SQL assignment. You get a more complex task...
From the following tables write a SQL query to count the number of customers with grades above the average in New York City. Return grade and count. Sample table : Customer customer_id cust_name city grade salesman_id --- --- --- --- --- 3002 Nick Rimando New York 100 5001 3005 ...
String predicate pushdown leverages the primary/secondary dictionary created for columns to improve the query performance. 例如,請考慮數據列群組內包含100個相異字串值的字串資料行區段。 假設有一百萬個資料列,每個相異字串值平均被參考 10,000 次。 使用字串述詞下推功能,查詢操作會根據字典中的值計算出...
Mastering SQL requires lots of practice. In this article, I took 5 tricky questions and explained the approaches to solve them. The specialty of SQL is that each query can be written in many different ways. Do feel free to share your approaches in the responses. I hope you learned somethin...