PREVIEW and EXPLAIN in Wonderful Relations
PREVIEW Query
The PREVIEW function allows users to preview a query before execution. It provides a readable SQL representation of the query, including selected fields, joins, and conditions.
Visual PREVIEW: SHOW Query
The following image displays a query preview, showing how a query is structured.
EXPLAIN Query
The EXPLAIN function is used for query analysis and optimization.
It provides insights into how a query will be executed, including: • Table access methods (e.g., full scan, index usage) • Join strategy • Estimated rows processed • Filtering efficiency
Visual Example
EXPLAIN Query
The following image demonstrates an EXPLAIN output, showing details about table usage and indexing: 