Allows a large table to be broken up into a number of smaller partitions which can be queried much more quickly than the table as a whole a union all view is built over the top to provide the original functionality Check constraints or where clauses provide partition elimination capabilities S...
Example 12-3 Using EXPLAIN PLAN with the INTO Clause EXPLAIN PLAN INTO my_plan_table FOR SELECT last_name FROM employees; You can specify a statement ID when using the INTO clause. EXPLAIN PLAN SET STATEMENT_ID = 'st1' INTO my_plan_table FOR SELECT last_name FROM employees; See Also...
An example appears in "Bitmap Indexes and EXPLAIN PLAN" on page 23-10. OR Computes the bitwise OR of two bitmaps. CONNECT BY A retrieval of rows in a hierarchical order for a query containing a CONNECT BY clause. CONCATENATION An operation that accepts multiple sets of rows and ...
Sort is used to sort data in ascending order (ASC) or descending order (DESC), which is usually used with the ORDER BY clause. In this example, data in the l_shipdate column of the TPC-H lineitem table is sorted. EXPLAIN SELECT l_shipdate FROM public.lineitem ORDER BY l_shipdat...
Explain with one example or more: Under what circumstance might the employer bypass a senior employee and promote a junior employee when the labor agreement (contract) contains a "seniority" clause? You may use the table below to better assist with...
主语从句例句讲解（Explain sth.）subject clause Subject clause (Subject, Clause)Definition: sentences that act as subjects in a compound sentence are called subject clauses Part 1: the regular subject clause, that is, the sentence acts as a subject in the compound sentence The subject tense: ...
<unionM,N>: The row refers to the union of the rows with id values of M and N. <derivedN>: The row refers to the derived table result for the row with an id value of N. A derived table may result, for example, from a subquery in the FROM clause. <subqueryN>: The row ...
Some of these factors include: » Data skew » Multiple single column predicates on a single table » Function wrapped columns in the WHERE clause predicates » Complex expressions In the previous example there is a data skew in the EMPLOYEES table. There is not an even number of ...
EXPLAIN shows the execution plan of an SQL statement.The execution plan shows how the tables referenced by the statement will be scanned - by plain sequential scan, index
<unionM,N>: The row refers to the union of the rows with id values of M and N. <derivedN>: The row refers to the derived table result for the row with an id value of N. A derived table may result, for example, from a subquery in the FROM clause. <subqueryN>: The row ...