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  1. Richard To
    Thread

    How to tune SQL in a Database Object with Plan Guide for SQL Server?

    Leveraging Plan Guides in MS SQL Server can prove beneficial for optimizing the performance of a particular query within database objects like...
    Thread by: Richard To, Aug 25, 2023, 0 replies, in forum: SQL Server
  2. Richard To
    Thread

    How to use ROWID to improve an UPDATE statement for Oracle?

    Here the following is an Update SQL with a subquery that updates the EMPLOYEE table if the emp_dept satisfies the records returned from a...
    Thread by: Richard To, Jul 4, 2022, 0 replies, in forum: Oracle
  3. Richard To
    Thread

    How to index SQL with aggregate function SQL for Oracle?

    Here the following is an example SQL shows you that select the maximum emp_address which is not indexed in the EMPLOYEE table with 3 million...
    Thread by: Richard To, Feb 21, 2022, 0 replies, in forum: Oracle
  4. Richard To
    Thread

    How to build indexes for multiple Max() functions for SQL Server?

    For some SQL statements with multiple Max() functions in the select list and nothing in the Where clause, we have different methods to create new...
    Thread by: Richard To, Jan 24, 2022, 0 replies, in forum: SQL Server
  5. Richard To
    Thread

    How is the order of the columns in a composite index affecting a subquery performance for Oracle?

    We know the order of the columns in a composite index will determine the usage of the index or not against a table. A query will use a composite...
    Thread by: Richard To, Jan 10, 2022, 0 replies, in forum: Oracle
  6. Richard To
    Thread

    Do not undermine your SQL Server’s potential ability

    For some SQL statements that are failed to be tuned by syntax rewrite, hints injection, and all necessary indexes are built, people may think that...
    Thread by: Richard To, Dec 8, 2021, 0 replies, in forum: SQL Server
  7. Richard To
    Thread

    How to use ORDERED Hint to Tune a SQL with subquery for Oracle?

    Here the following is the description of the ORDERED hint. The ORDERED hint causes Oracle to join tables in the order in which they appear in the...
    Thread by: Richard To, Nov 12, 2021, 0 replies, in forum: Oracle
  8. Richard To
    Thread

    How to Tune SQL Statements with NO_RANGE_OPTIMIZATION Injection?

    There are some SQL statements with performance problem can be tuned by Hints injection only. Here is an example to show you how to use...
    Thread by: Richard To, Oct 8, 2021, 0 replies, in forum: MySQL
  9. Richard To
    Thread

    How to tune a SQL that cannot be tuned?

    Some mission-critical SQL statements are already reached their maximum speed within the current indexes configuration. It means that those SQL...
    Thread by: Richard To, Sep 13, 2021, 0 replies, in forum: Oracle
  10. Richard To
    Thread

    How to Tune SQL Statement with CASE Expression for SQL Server II?

    We have discussed how to tune a CASE expression SQL with hardcoded literals in my last blog: How to Tune SQL Statement with CASE Expression for...
    Thread by: Richard To, Aug 19, 2021, 0 replies, in forum: SQL Server
  11. Richard To
    Thread

    How to Tune SQL Statement with CASE Expression for SQL Server I?

    Here the following is a simple SQL statement with a CASE expression syntax. SELECT * FROM EMPLOYEE WHERE CASE when emp_id < 1001000 then 'Old...
    Thread by: Richard To, Jul 19, 2021, 0 replies, in forum: SQL Server
  12. Richard To
    Thread

    How to Tune SQL Statements to Run SLOWER… but Make Users Feel BETTER (MySQL)?

    Your end-users may keep on complaining about some functions of their database application are running slow, but you may found that those SQL...
    Thread by: Richard To, May 19, 2021, 0 replies, in forum: MySQL
  13. Richard To
    Thread

    How to Tune Bad Performance SET ROWCOUNT SQL Statements for SQL Server?

    Some SQL statements will be running very slow after SET ROWCOUNT or TOP is used. SET ROWCOUNT and TOP are used to tell SQL Server to select a...
    Thread by: Richard To, Apr 28, 2021, 0 replies, in forum: SQL Server
  14. Richard To
    Thread

    How to Tune SQL Statement with IN Operator with an Expression List for SQL Server?

    The following is an example shows a SQL statement with an IN List expression. The SQL retrieves records from EMPLOYEE table that EMP_DEPT should...
    Thread by: Richard To, Apr 7, 2021, 0 replies, in forum: SQL Server
  15. Richard To
    Thread

    How to Tune SQL Statements with CONCAT Operator for MySQL?

    There may be some business requirements that need to compare concatenate strings and column with a given unknown length of the bind variable....
    Thread by: Richard To, Feb 19, 2021, 0 replies, in forum: MySQL
  16. Richard To
    Thread

    How to Tune SQL statement with Transitive Dependency Improvement for MySQL?

    The following is an example shows a SQL statement with two conditions “emp_dept=dpt_id and emp_dept<'L'” . select * from employee, department...
    Thread by: Richard To, Jan 22, 2021, 0 replies, in forum: MySQL
  17. Richard To
    Thread

    How to Tune SQL Statement with Driving Path Control for MySQL?

    The following is an example shows a SQL statement with two potential table join paths. “Employee to Department” and “Department to Employee” are...
    Thread by: Richard To, Jan 4, 2021, 0 replies, in forum: MySQL
  18. Richard To
    Thread

    How to Tune SQL with Exists Operator in Certain Environment for Oracle?

    Here is an example SQL that retrieves data from EMPLOYEE table with “emp_id < 710000” and employee’s department code exists in DEPARTMENT table....
    Thread by: Richard To, Dec 18, 2020, 0 replies, in forum: Oracle
  19. Richard To
    Thread

    How to Tune SQL with SEMI JOIN by Hints INDEX_DESC Injection for Oracle?

    Semi-join is introduced in Oracle 8.0. It provides an efficient method of performing a WHERE EXISTS or WHERE IN sub-queries. A semi-join returns...
    Thread by: Richard To, Dec 6, 2020, 0 replies, in forum: Oracle
  20. Richard To
    Thread

    How to Tune SQL Statement with Multiple Union in Subquery for MySQL?

    The following is an example shows a SQL statement with two union operator in a subquery. The SQL retrieve records from EMPLOYEE table that EMP_ID...
    Thread by: Richard To, Nov 30, 2020, 0 replies, in forum: MySQL
Showing results 1 to 20 of 26
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