mirror of https://gitlab.com/octtspacc/OcttKB
29 lines
1.7 KiB
Plaintext
29 lines
1.7 KiB
Plaintext
created: 20231223234312578
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creator: Octt
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modified: 20240119162211752
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modifier: Octt
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title: Database
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<<^wikipediaframe Database>>
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!! SQL (Structured Query Language)
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<<^wikipediaframe SQL>>
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* [[SQL Tutorial - Essential SQL For The Beginners|https://www.sqltutorial.org/]], //helps you get started with SQL quickly and effectively through many practical examples.//
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* [[SQL Server reverse order after using desc|https://stackoverflow.com/questions/12534248/sql-server-reverse-order-after-using-desc]] --- just use a subselect subquery, `SELECT * FROM (... ORDER BY x DESC) _ ORDER BY x ASC`
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* [[How to count instances of character in SQL Column|https://stackoverflow.com/questions/1860457/how-to-count-instances-of-character-in-sql-column#1860478]] --- `SELECT LEN(col) - LEN(REPLACE(col, 'x', ''))`
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** [[SQL String: Counting Words inside a String|https://stackoverflow.com/questions/41952250/sql-string-counting-words-inside-a-string]] --- various methods more specially catered for counting words, than the naive space counting
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** Note: for counting in many rows together, the `SUM()` function must be used, [[or else you will go mad like me|https://chat.openai.com/share/5883b4c6-37cf-40e3-b735-9cd52b26020c]]
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!!! MySQL \ MariaDB
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<<^wikipediaframe MySQL>>
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<<^wikipediaframe MariaDB>>
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* [[How to install MySQL (MariaDB) on Android with Termux|https://parzibyte.me/blog/en/2019/04/16/install-mysql-mariadb-android-termux/]]
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* [[--skip-grant-tables option cannot execute statement|https://stackoverflow.com/questions/54751024/skip-grant-tables-option-cannot-execute-statement]] --- in `mysql>` execute `flush privileges`
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* [[MySQL LENGTH() Function|https://www.w3schools.com/sql/func_mysql_length.asp]] (not LEN on MySQL!)
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