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Table of Contents Basic Query Statements Data Manipulation Statements Table Structure Operations Index Operations View Operations Stored Procedures and Functions Transaction Control Permission Management Data Type Differences Common Function Comparisons Basic Query Statements SELECT Queries Oracle -- Basic query SELECT col_a, col_b FROM tar ...

Access paths determine how the database retrieves data from a table—typically via primary key scans or secondary indexes. The efficiency of a query hinges on selecting the optimal path, as full table scans scale linearly with data volume. When an index exists, it can drastically reduce I/O by limiting the scanned rows. However, if the optimizer ...

OceanBase uses a cost-based optimizer with hint syntax similar to Oracle. There are key operational details to note: When executing hinted SQL via MySQL client, connect with -c to avoid client-side stripping of hint comments Unrecognized server hints are silently ignored instead of throwing errors Hints only modify optimizer plan generation lo ...

OceanBase's architectural foundation differs significantly from traditional relational databases, which directly impacts SQL performance tuning strategies. Architectural Distinctions LSM-Tree Storage Engine Data is organized into static components (SSTables) and dynamic components (MemTables). Performance for many query improves after a major c ...