oracle sql practice exercises

Oracle Database SQL --- one of selectPrefaceI have already explained in the previous article that the best learning is practice! Therefore, my learning is based on practice. In all SQLThe most basic statement is the query statement. Therefore, I also learned from the select statement. (In fact, this part of the author)

Tags: Tips control oracl Programmer Practice Union Multiple full table scans causeI. Use of the SQL language1. in operatorThe advantages of SQL in write are easier to write and easy to understand, which is more suitable for modern software development style.But SQL performance with in is always lower, and the steps tak

Solutions for querying paging data using SQL Server SQL statements: You must select 3,000th records on page 1 of tbllendlist, with 100 records on each page. ------------------------- ----------Method 1:----------Select Top 100 * From tbllendlistWhere fldserialno not in(Select top 300100 fldserialno from tbllendlistOrder by fldserialno)Order by fldserialno ----------Method 2:----------Select Top 100 *F

following features: 1. When exporting data, you can filter the data to be exported and write SQL statements in the BCP command; 2. You can simply format the data to be imported (such as removing spaces and replacing unwanted characters) and process the data in the CTL file of SQLLDR. 3. Logs can be obtained throughout the execution process, making it easier to handle errors. Certificate ---------------------------------------------------------------

, number of physical reads and writes, execution plan, and some additional information4If Level 1, includes additional information about the bound variable. Primarily data types, precision, and values used each time they are executed8Same level 1, plus details about the wait time. To handle each wait in the process, provide the following information: The name of the Wait time, the duration, and some additional parameters that indicate the resources you are waiting for ASimultaneous start level 4

separator, and fixed-width text files. However, in practice, most text files are separated by commas. The second is the control file. The control file is used to establish a one-to-one correspondence between data files and Oralce data table fields. Simply put, putting a certain content in the data file on the field in the Oracle data table is the main role of the control file. There is also a file, which i

time.Number of rows processed, number of rows processed, number of logical reads, number of physical reads and writes, execution plan, and additional information 4If Level 1 includes additional information about the variable to be bound. Mainly data types, precision, and values used for each execution 8Level 1, plus detailed information about the wait time. For each wait in the processing process, the following information is provided: the name, duration, and some additional parameters of the w

SQL single-line functions in Oracle databases-character FunctionsThis learning is about character functions.Character FunctionsCharacter functions can also be divided into case-insensitive conversion functions and character processing functions.Case-sensitive conversion functions1. LOWER: Convert to lower case [SQL] select LOWER ('

Preface The best way to learn is practice! Therefore, my learning is based on practice. The most basic SQL statement is the query statement. Therefore, I also learned from the select statement. (In fact, this part of the author) has been mastered, but it is still necessary to grasp it again. For the previous study, we mainly used some existing tables in the

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adjustment is described earlierThree different methods.Common tuning methods for top sql:1, if the statistical information is not allowed or because the CBO calculates some of the SQL cost of the formula used to cause SQL performance problems, we can by re-collect statistics, or manuallyModify the statistics, or use hint to resolve them.Comment: How to collect s

SQLLDRData: Storage of BCP export and SQLLDR importSQL: Holds SQL executed by Oracle, with an "EXIT" at the end of the SQL statement in each SQL file.Data_export_import_3in1.bat: Executes all batch files in the bat sequentially, and outputs the execution log information for each step, see. Run this file to complete th

, resulting in data import failure. If the data field to be imported is too long and exceeds the maximum length limit of the data table, data import may fail. Using the SQL * Loader import tool, you can separate the records that do not comply with the rules and store them in an independent file. Data that meets the rules can be imported normally. In this way, the data import accuracy can be improved.Next, let's take a look at how to use this

---- -------------------- -------------------- --------- --------- ---------- ---------- ---------------Jason Martin 25-jul-96 25-jul-06 1234.56 Toronto ProgrammerAlison Mathews 21-mar-76 21-feb-86 6661.78 Vancouver TesterJames Smith 12-dec-78 15-mar-90 6544.78 Vancouver TesterCelia Rice 24-oct-82 21-apr-99 2344.78 Vancouver ManagerRobert Black 15-jan-84 08-aug-98 2334.78 Vancouver TesterLinda Green 30-jul-87 04-jan-96 4322.78 New York TesterDavid Larry 31-dec-90 12-feb-98 7897.78 New York Manag

The Oracle tutorial you are looking at is: Oracle SQL Performance Tuning Series Learning Ii. 4. Select the most efficient table name order (valid only in the Rule-based optimizer) The Oracle parser processes the table names in the FROM clause in Right-to-left order, so the last table in the FROM clause (the underlying

oracle| Data | Database in the database operation is often the case occurs, due to a momentary negligence and mistakenly deleted or mistakenly changed some important data, in addition to some important tasks need to run periodically. Obviously, the first kind of problem is mainly data backup and recovery, the latter is mainly the task scheduling of the system. In this paper, we will give a solution to these two types of problems from the perspective o

Label:In SQL Server has been using the DTS Extract data, but DTS Microsoft only support to 2008, to 2012 there is no such tool, now need to build a channel between SQL Server and Oracle, with this channel, Extract the data from Oracle into the SQL Server database. Environmen

in data import failure. If the data field to be imported is too long and exceeds the maximum length limit of the data table, data import may fail. Using the SQL * Loader import tool, you can separate the records that do not comply with the rules and store them in an independent file. Data that meets the rules can be imported normally. In this way, the data import accuracy can be improved. Next, let's take a look at how to use this

-end enterprise database software. Oracle Database Engineer is one of the most urgently needed technical personnel in the enterprise, Oracle database Engineer is a high-paying career, the primary DBA has a salary of about 10W, and the intermediate DBA has a minimum annual salary of 20w+, while the domestic senior database expert has exceeded 100W. This course is an essential part of your

How to Write high-quality SQL statements in Oracle databases and diagnose and adjust SQL statements with performance problems in Oracle databases is an inevitable challenge for DBAs in ORACLE Database practice. Next let's analyze