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SQL

Coding tips and build notes by Mahir Faysal, a student web developer in Bangladesh: tested Python, HTML, CSS, JavaScript and PHP tutorials, plus notes from my Next.js and Gemini projects. Sample posts are marked and drafts stay in the admin area.

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Coding tips

MySQL Delete Duplicate Rows but Keep One (Find Them First)

Find duplicates with GROUP BY and HAVING, preview them with ROW_NUMBER(), then delete all but one with a self-join. Error 1093, NULLs, case and spaces, and a UNIQUE key.

October 7, 2026 · 19 min read · 0 views

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