Showing posts with the label Start services

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SQL Interview Success: Unlocking the Top 5 Frequently Asked Queries

 Here are the five top commonly asked SQL queries in the interviews. These you can expect in Data Analyst, or, Data Engineer interviews. Top SQL Queries for Interviews 01. Joins The commonly asked question pertains to providing two tables, determining the number of rows that will return on various join types, and the resultant. Table1 -------- id ---- 1 1 2 3 Table2 -------- id ---- 1 3 1 NULL Output ------- Inner join --------------- 5 rows will return The result will be: =============== 1  1 1   1 1   1 1    1 3    3 02. Substring and Concat Here, we need to write an SQL query to make the upper case of the first letter and the small case of the remaining letter. Table1 ------ ename ===== raJu venKat kRIshna Solution: ========== SELECT CONCAT(UPPER(SUBSTRING(name, 1, 1)), LOWER(SUBSTRING(name, 2))) AS capitalized_name FROM Table1; 03. Case statement SQL Query ========= SELECT Code1, Code2,      CASE         WHEN Code1 = 'A' AND Code2 = 'AA' THEN "A" | "A

2 Exclusive Ways to Start Kafka Services

The Kafka services start or stop you can do in two ways. Those are  Systemd  and  Systemctl  (sudo user). Below, you will find the commands for these two methods. How to start/stop Kafka service Here are exclusive ways. With these, you can start or stop Kafka services .   1. Systemd service The concept of unit files people who worked on Linux servers have familiarity with it. Also, they know creating the unit file to use by systemd. To summarize,  it initializes and maintains components throughout the system . This means that you can define ZooKeeper and Kafka as unit files, which then will be used by systems. Commands The first command starts the service, and the second command stops the service. ... [Service] ... ExecStart=/opt/kafkainaction/bin/ ExecStop= /opt/kafkainaction/bin/ 2. Systemctl by Sudo (root) user The root user can start or stop the Kafka services. This is more like front-end processing. This way of executing is called