Database Administration
Add a Generated Column in MySQL
A generated column holds a value MySQL computes from the rest of the row, so it can never drift out of step. This tutorial…
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Category: Database Administration
Database Administration
Store and Query JSON Data in MySQL
Use the JSON column type to store documents MySQL actually understands. This tutorial inserts JSON, reads keys with JSON_EXTRACT and the ->> shorthand, edits…
Database Administration
Query Hierarchical Data With a Recursive CTE in MySQL
Walk a category tree stored as a flat parent_id column using WITH RECURSIVE. This tutorial builds the anchor and recursive member, adds a depth…
Database Administration
Write a Common Table Expression With WITH in MySQL
Name a query result with WITH so the rest of the statement reads it like a table. This tutorial rewrites a nested subquery as…
Database Administration
Rank Rows With ROW_NUMBER and RANK in MySQL
Number and rank rows in MySQL with the ROW_NUMBER, RANK and DENSE_RANK window functions. Learn how PARTITION BY restarts the count per group, how…
Database Administration
Format Dates in MySQL With DATE_FORMAT
One DATETIME, three presentations: the DATE_FORMAT specifiers that matter (minutes are %i, never %m), DATEDIFF and DATE_ADD arithmetic, a monthly report, and when the…