格式化与代码
SQL 索引推荐
Spot missing indexes from WHERE / JOIN / ORDER clauses.
Recommendations · 4
u.created_athighUsed in WHERE — high selectivity benefit
CREATE INDEX idx_u_created_at ON …(created_at);
p.author_idhighJoin column — index speeds up the lookup
CREATE INDEX idx_p_author_id ON …(author_id);
u.idhighJoin column — index speeds up the lookup
CREATE INDEX idx_u_id ON …(id);
postsmedORDER BY — composite index can avoid filesort
CREATE INDEX idx_posts ON …(posts);
编辑注
Understanding · B-trees by default — and the five other kinds for when they're not enough.
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常见问题
Quick answers.
›Which SQL dialects are supported?
The analyzer works with standard SQL syntax compatible with PostgreSQL, MySQL, and SQL Server. It focuses on identifyng `WHERE`, `JOIN`, and `ORDER BY` clauses common to all relational engines.
›Does this tool access my database?
No. The analyzer is a static parser that runs entirely in your browser. It evaluates the text of your query and does not require a connection to your live database infrastructure.
›Why does it suggest composite indexes?
Composite indexes are recommended when a query filters on multiple columns simultaneously. This allows the database engine to locate records more efficiently than using two separate single-column indexes.
›Are there risks to adding too many indexes?
Yes. While indexes speed up read operations, they slow down `INSERT`, `UPDATE`, and `DELETE` actions because the index must also be updated. Only implement recommendations for queries that run frequently or are noticeably slow.
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