Brett Haralson
Kansas City, Missouri, United States
282 followers
281 connections
282 followers
281 connections
About
Database Professional with over 10 years experience in database administration and…
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282 followers
Brett Haralson commented on a post
3y
That’s a tough one. Great job!
Brett Haralson replied to a comment
3y
While the optimizer might take care of the problem for you, I would tend to agree with Rafael. Why trust or rely on the engine to clean up our messes when we can understand why this is unnecessary and fix potentially bad form before it gets put into production, regardless of how little impact it might have? It reminds me of someone who throws their trash on the ground because a janitor will take care of it later.
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Brett Haralson liked thisBrett Haralson liked this𝐒𝐐𝐋 𝐈𝐧𝐭𝐞𝐫𝐯𝐢𝐞𝐰 𝐂𝐡𝐞𝐚𝐭𝐒𝐡𝐞𝐞𝐭: 𝐁𝐞 𝐉𝐨𝐛-𝐑𝐞𝐚𝐝𝐲 𝐅𝐫𝐨𝐦 𝐃𝐚𝐲 𝟏 SQL will never go out of demand. You’ll be asked queries even in Data Science, Backend Dev, ML, Analyst roles. Mastering the core blocks will 10× your interview game. Here’s the SQL Interview Cheatsheet you can revise anytime: 𝟏 ⤷ 𝐒𝐄𝐋𝐄𝐂𝐓 + 𝐅𝐑𝐎𝐌 + 𝐖𝐇𝐄𝐑𝐄 ⤷ Pull only the data you need using WHERE → Example: SELECT name FROM employees WHERE salary > 50000; 𝟐 ⤷ 𝐎𝐑𝐃𝐄𝐑 𝐁𝐘 + 𝐃𝐈𝐒𝐓𝐈𝐍𝐂𝐓 + 𝐋𝐈𝐌𝐈𝐓 ⤷ Sort, deduplicate, and restrict output rows → Example: SELECT DISTINCT city FROM customers ORDER BY city LIMIT 5; 𝟑 ⤷ 𝐂𝐎𝐔𝐍𝐓 + 𝐀𝐕𝐆 + 𝐒𝐔𝐌 + 𝐌𝐈𝐍 + 𝐌𝐀𝐗 ⤷ Learn how aggregation works → Example: SELECT AVG(age), COUNT(*) FROM students; 𝟒 ⤷ 𝐆𝐑𝐎𝐔𝐏 𝐁𝐘 + 𝐇𝐀𝐕𝐈𝐍𝐆 ⤷ Use for summarization by category → Example: SELECT department, AVG(salary) FROM employees GROUP BY department HAVING AVG(salary) > 60000; 𝟓 ⤷ 𝐉𝐎𝐈𝐍𝐒 — 𝐈𝐍𝐍𝐄𝐑, 𝐋𝐄𝐅𝐓, 𝐑𝐈𝐆𝐇𝐓, 𝐅𝐔𝐋𝐋 ⤷ Merge tables based on relationships → Example (LEFT JOIN): SELECT a.name, b.department FROM employee a LEFT JOIN dept b ON a.dept_id = b.id; 𝟔 ⤷ 𝐒𝐔𝐁𝐐𝐔𝐄𝐑𝐈𝐄𝐒 + 𝐂𝐓𝐄𝐬 ⤷ Break complex queries into manageable chunks → Example (CTE): WITH top_sales AS ( SELECT name, sales FROM sellers WHERE sales > 100000 ) SELECT * FROM top_sales; 𝟕 ⤷ 𝐂𝐀𝐒𝐄 𝐖𝐇𝐄𝐍 + 𝐂𝐎𝐀𝐋𝐄𝐒𝐂𝐄 + 𝐍𝐔𝐋𝐋 𝐇𝐀𝐍𝐃𝐋𝐈𝐍𝐆 ⤷ Build conditional logic into SELECT → Example: SELECT name, CASE WHEN score > 90 THEN 'Excellent' WHEN score > 70 THEN 'Good' ELSE 'Average' END AS performance FROM results; 𝟖 ⤷ 𝐔𝐍𝐈𝐎𝐍 + 𝐈𝐍𝐓𝐄𝐑𝐒𝐄𝐂𝐓 + 𝐄𝐗𝐂𝐄𝐏𝐓 ⤷ Combine results across queries → Example: SELECT name FROM classA UNION SELECT name FROM classB; 𝟗 ⤷ 𝐈𝐍𝐃𝐄𝐗𝐄𝐒 + 𝐏𝐑𝐈𝐌𝐀𝐑𝐘 𝐊𝐄𝐘 + 𝐅𝐎𝐑𝐄𝐈𝐆𝐍 𝐊𝐄𝐘 ⤷ Design your schema for optimal speed and data integrity 𝟏𝟎 ⤷ 𝐏𝐑𝐀𝐂𝐓𝐈𝐂𝐄 + 𝐐𝐔𝐄𝐒𝐓𝐈𝐎𝐍𝐒 ⤷ You only get good at SQL by doing it Try sites like: → sqlzoo.net → mode.com/sql-tutorial → https://lnkd.in/gyy_ccaM → stratascratch.com 𝐓𝐋;𝐃𝐑: ⤷ Learn SQL execution from SELECT to CTE ⤷ Master joins, filters, aggregations, and subqueries ⤷ Use this cheat sheet daily till it’s second nature ⤷ You don’t need 200 functions just know 20 that actually work in interviews Want a 4K PDF version? Just reply with SQL --- 📕 400+ 𝗗𝗮𝘁𝗮 𝗦𝗰𝗶𝗲𝗻𝗰𝗲 𝗥𝗲𝘀𝗼𝘂𝗿𝗰𝗲𝘀: https://lnkd.in/gv9yvfdd 📘 𝗣𝗿𝗲𝗺𝗶𝘂𝗺 𝗗𝗮𝘁𝗮 𝗦𝗰𝗶𝗲𝗻𝗰𝗲 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝗥𝗲𝘀𝗼𝘂𝗿𝗰𝗲𝘀 : https://lnkd.in/gPrWQ8is 📙 𝗣𝘆𝘁𝗵𝗼𝗻 𝗗𝗮𝘁𝗮 𝗦𝗰𝗶𝗲𝗻𝗰𝗲 𝗟𝗶𝗯𝗿𝗮𝗿𝘆: https://lnkd.in/gHSDtsmA 📗 45+ 𝗠𝗮𝘁𝗵𝗲𝗺𝗮𝘁𝗶𝗰𝘀 𝗕𝗼𝗼𝗸𝘀 𝗘𝘃𝗲𝗿𝘆 𝗗𝗮𝘁𝗮 𝗦𝗰𝗶𝗲𝗻𝘁𝗶𝘀𝘁 𝗡𝗲𝗲𝗱𝘀: https://lnkd.in/ghBXQfPc --- Join What's app channel for jobs updates: https://lnkd.in/gu8_ERtK 📸/ datemur.com
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Brett Haralson liked thisBrett Haralson liked thisView my verified achievement from GitHub.GitHub Foundations was issued by GitHub to Rayjan Michael Wilson.GitHub Foundations was issued by GitHub to Rayjan Michael Wilson.
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Brett Haralson liked thisBrett Haralson liked thisI'm happy to announce that I have returned to the database unit of SolarWinds as Sr Technical Marketing Manager. If you've missed seeing me at conferences, the days of me being absent are over. Cheers!
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Brett Haralson liked thisFinally completed all of the AWS Certifications with help of my family and friends support Thank you #aws . 🎉🎉🎉🎉🎉
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