MySQL Joins [13 exercises with solution] [An editor is available at the bottom of the page to write and execute the scripts. Go to the editor] 1. Write a MySQL query to find the addresses (location_id, street_a
This section provides answers to frequently asked questions. What is the maximum number of MySQL servers in a group? A group can consist of maximum 9 servers. Attempting to add another server to a group with 9 members causes the request to join to be refused. This limit has been identified...
Conditional Joins in MySQL Posted on February 7, 2010, 1:43 pm, by Hazan Ilan, underCool MySQL Queries. One way to do a “Conditional Join” in MySQL is by using a “LEFT JOIN”. Create a “LEFT JOIN” for each condition and combine the results into one column using an “IF” sta...
SQL Interview Questions UNION vs. UNION ALL Inner vs. Outer joins SQL Key Definition Differences between Primary and Foreign Keys Natural Key In Database Secondary Key Simple key in SQL Superkey Example What is Referential Integrity Having vs. Where clause How do database indexes work? What is...
Reliability: It endorses joins, views, stored procedures, and foreign keys in various languages. Because of the write-ahead logging feature, PostgreSQL is fault-tolerant and supports data backup and recovery. Adaptive: It endorses stored procedures and functions and contains more capabilities and fea...
Some joins are also better than others. For example, if you have a star join with dimension tables being small, it would not slow things down too much. On the other hand, a join of a few large tables, which is completely disk-bound, can be very slow. One of the reasons elevating ...
1 male | | Buffy | 4 | 5 puppies, 2 female, 3 male | | Buffy | 5 | 3 puppies, 3 female | +---+---+---+ There are several things to note about this query: • The FROM clause joins two tables because the query needs to pull information from both of them. • When com...
Joins or Subqueries ? The main advantage of a join is that it executes faster. The performance increase might not be noticeable by the end user. However, because the columns are specifically named and indexed and optimized by the database engine, the retrieval time almost always will be faster...
MySQL CONCAT using JOINS and wildcard character Try Quries by yourself Example of MySQL Concat Function using agruments One argument: mysql> SELECT CONCAT('w3resource'); +---+ | CONCAT('w3resource') | +---+ | w3resource | +---+ 1 row in set (0.00 sec) Two or more arguments: mys...
23.6.6: Can you insert into views that are based on joins? Questions and Answers 23.6.1: Does MySQL 5.4 have table snapshots? No. 23.6.2: Does MySQL 5.4 have materialized views? No. 23.6.3: What happens to a view if an underlying table is dropped or renamed? After a view...