Returns count of number of rows in one or more bitmap
This operation is implemented in the following versions
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This example was developed using Oracle 9.2.0.1 on Windows 2000
This example requires the following table and index definitions
CREATE TABLE t1 (c1 NUMBER,c2 NUMBER); CREATE BITMAP INDEX i1 ON t1 (c1);
The table does not need to be analysed. NOT NULL constraints are not required for the indexed column(s) as bitmap indexes include a bitmap for NULL values
The statement
SELECT /*+ INDEX (t1 i1) */ COUNT(*) FROM t1;
generates the following execution plan
0 SELECT STATEMENT Optimizer=CHOOSE 1 0 SORT (AGGREGATE) 2 1 BITMAP CONVERSION (COUNT) 3 2 BITMAP INDEX (FULL SCAN) OF 'I1'