Tag: databases

100

0

1

10

This value causes the optimizer to the rule-based approach for all SQL statements in the session regardless of the presence of statistics and to optimize with a goal of best throughput

This value causes the optimizer to the rule-based approach for all SQL statements in the session in regard of the presence of statistics and to optimize with a goal of best throughput

This value causes the optimizer to the cost-based approach for all SQL statements in the session regardless of the presence of statistics and to optimize with a goal of best throughput

This value causes the optimizer to the cost-based approach for all SQL statements in the session regard of the presence of statistics and to optimize with a goal of best throughput

SELECT TRUNC(TO_DATE('12-Feb-99','DD-MON-YY'), 'YEAR') "Date " FROM DUAL;

SELECT TRUNC(TO_DATE('12-Feb-99','DD-MON-YY'), 'YEAR') FROM DUAL;

TRUNCATE=To_Date('09-Jan-02,DD-MON-YY,'YEAR',"Date" from Dual;

Date =TRUNCATE(To_DATE('09-Jan-02','DD-MON-YY'),'YEAR'),'YEAR)"DATE: from DUAL;

DELETE FROM table_name WHERE ROWID IN (SELECT MAX (ROWID) FROM table_name GROUP BY duplicate_values_field_name);

DELETE FROM table_name WHERE ROWID NOT IN (SELECT MAX (ROWID) FROM table_name GROUP BY duplicate_values_field_name);

DELETE FROM table_name WHERE ROWID IN (SELECT MIN (ROWID) FROM table_name GROUP BY duplicate_values_field_name);

DELETE FROM table_name WHERE ROWID IN (SELECT AVG (ROWID) FROM table_name GROUP BY duplicate_values_field_name);

Primary key access

Access via unique index

Table access by ROWID

Full table scan

DROP

DELETE

CASCADE

TRUNCATE

INSTR

SUBSTRING

SUBSTR

POS

TO_CHAR

LOWER

LPAD

MAX

CEIL

The number of CPUs on the server

The degree of parallelism on the tables

The use of bitmap indexes

The quality of the SQL optimization

Indexes are only used in special cases

Indexes are used to make table storage more efficient

Indexes rarely make a difference in SQL performance

Indexes exist solely to improve query speed