If SQL query performance is poor or query results do not meet expectations, you can execute the EXPLAIN and EXPLAIN ANALYZE statements in Hologres to obtain execution plans of query statements. This way, you can optimize query statements or database structures. This topic describes how to execute...
the MySQL optimizer considers many techniques to efficiently performthe lookups involved in an SQL query. A query on a huge table can be performedwithout reading all the rows; a join involving several tables can be performedwithout comparing every combination of rows. The set of operations...
In addition to flexible licensing options for SQL Server, there are also Windows Server licensing options that can be taken advantage of. These Windows Server options are known as the Azure Hybrid Benefit (AHB). Similar to applying a SQL Server license you already have purchas...
SQL- Where Clause: Answer and Explanation: The purpose of ''Where'' clause in a query is to specify, to limit and to filter a condition when getting data from a table. Tables can be either be... Learn more about this topic:
tableThe table and index used in a scan operation in a statement, in the form{table name}@{index name}. spansThe interval of the key space read by the processor.FULL SCANindicates that the table is scanned on all key ranges of the index (also known as a "full table scan" or "unlim...
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This plan shows execution of aSELECTstatement. IndexPER_PEOPLE_F_N54is used in a range scan operation. The tablePER_ALL_PEOPLE_Fis accessed throughROWID.ROWIDs are obtained from the index in the previous step for keys that meet theWHEREclause criteria. When the table is accessed, any additio...
QSM-01030 materialized view, string, has PL/SQL functions in ENFORCED integrity mode Cause: A materialized view with PL/SQL functions in its definition cannot be used for query rewrite when query rewrite integrity is set to ENFORCED. Action: Consider running the query in STALE TOLERATED mode. ...
Supposethat MIN(c1) can be retrieved by reading one index row and MIN(c2) canbe retrieved by reading one row from a different index. That is, for eachcolumn c1 and c2, thereexists an index where the column is the first column of the index. In thiscase, one row is returned, produced...
INDEX RANGE SCAN EMP_I1 [ANALYZED] In this case the index is sorted so ther rows will be returned in the order of the index hence a sort is unecessary. SQL> explain plan for select /*+ Full(emp) */ empno,ename from emp where empno> 7876 order by empno; ...