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The Oracle tutorials being looked at are: Oraclepl/sql single-line functions and group functions. A 1 function is a program that has 0 or more parameters and has a return value. In SQL, Oracle builds a series of functions that can be called
Correspondence between data types in SQL Server and data types in MySQL (EXT): 78899477One, SQL Server and MySQL data storage differences1, datetime in SQL Server, reserved to microseconds (the second decimal point 3 bits), and MySQL only retained to the second, whether the
[]: Specifies a character, string, or range that requires matching objects to be any of them. [^]: The value is also [] the same, but it requires that the matched object be any character other than the specified character. Four query results sort correlation functions SQL Aggregate (collection) functionCalculates the value obtained from the column, returning a s
format control.
Set and change the date display format, convert data types, use functions such as NVL to process null values, and implement IF-THEN-ELSE multi-path branch logic.
Continued 2: the conversion function does not change the field type and value of the table data. It is equivalent to copying a copy of the data. The converted data is the copied data.
Implicit and explicit conversions are supported
function | An explanatory function is a program that has 0 or more parameters and has a return value. In SQL, Oracle builds a series of functions that can be called SQL or PL/SQL statements, and functions fall into two main categories:
Single line function
Group
SQL ServerType
C #Type
Exact number
Bigint
Integer Data from-2 ^ 63 (-9223372036854775808) to 2 ^ 63-1 (9223372036854775807) (All numbers ). The storage size is 8 bytes.
Int64
Int
Integer Data from-2 ^ 31 (-2,147,483,648) to 2 ^ 31-1 (2,147,483,647) (All numbers ). The storage size is 4 bytes.IntThe SQL-92Inte
avg (), count (), max (), min (), sum (), etc.
For example, select avg (sal), max (sal), min (sal), sum (sal), max (hiredate), min (hiredate) from emp;
Continued 1: multiple functions can be implemented using a single row function in Oracle system functions, such as data calculation and data output format control.
Set and change the date display format, convert data ty
according to their own requirements;User-defined function, as the name implies, is a number of user-defined functions;User-defined functions are divided into two categories: table-valued functions and scalar-valued functions;There are two types of table-valued
PL/SQL single-line functions and group functionsA function is a program that has 0 or more parameters and has a return value. Oracle has built a series of functions in SQL, which can be called SQL or PL/SQL statements, and
first batch of 500 data records, and create a unique sessionID for this query, each time you click the "load more" button on the interface, you can use this sessionID and the two parameters that have been returned to the server to call the RPC interface on the server to continue to return the next batch of data.
If you click the "load all" button, start a background worker thread on the client and keep running the "load more" process.
The core is to record the sessionID of the current query se
String typeFixed length: char nchar n denotes Unicode encodingVariable length: varchar2 nvarchar2Numeric type: Number (p,s) P: integer digits, S decimal placeInteger integersBinary_float Single floating pointBinary_double Double floating pointFloat (n) floating-point number n indicates precisionDay Type: DateTIMESTAMPA user-defined function is a block of code stored in a database that can be returned to the calling program. Called as ifSystem functions
Tags: data-mod function String type proc UI decimal oat Tracking String typeFixed length: char nchar n denotes Unicode encodingVariable length: varchar2 nvarchar2 Numeric type: Number (p,s) P: integer digits, S decimal placeInteger integersBinary_float Single floating pointBinary_double Double floating pointFloat (n) floating-point number n indicates precisionDay Type: DateTIMESTAMP A user-defined function is a block of code that is stored in a database and is capable of returning values to the
Label:Original: SQL Server function Full solution One: Data type conversion functionWhen you work with values of different data types at the same time, SQL Server typically automatically makes a hermit type conversion. Values that are similar to data types are valid, such as int and float, but for other data
salary of all employees above the department 20Select Ename,sal,deptno from emp where sal > All (select Sal from emp where deptno=20)> is a single-line operator, and the subquery is multiline, with all to resolve the syntax conflict, to meet the ' all ' requirementAttention:1. Cannot write order by in subquery2. Multiline subqueries cannot be matched by single-line operators3. Single-line subqueries can match multiple line operators4. Subqueries must be written in parentheses5. Sub-query to be
Beginners can from the query to the current PL/SQL content can be found in my notes here, I hope to help everyone, video resources in resources,My own full set of notes in notesThe SQL keywords that you can continue to use in PL $ are: UPDATE Delete insert Select--into commit rollback savepoint, it is important to note that the query is not the same as before.Plsql consists of three blocks: Declaration part
Label:An aggregate function evaluates a set of values and returns a single value. In addition to the count (number of statistics) function, the other aggregate functions ignore null values (NULL) in the formula. All aggregate functions are deterministic
One: Data type conversion functionWhen you work with values of different data types at the same time, SQL Server typically automatically makes a hermit type conversion. Values that are similar to data types are valid, such as int and float, but for other data types, such as Integer and character
UML (Unified Modeling Language): It is an object-oriented visual modeling language.
UML has three types of constructor blocks: Things, relationships, and graphs. Things are the abstraction of the most representative components in the model. links are the combination of things, and graphs aggregate related things.
There are nine types of diagrams in UML:
1. use ca
return columns and aggregate columns of the basic row in the same row. For example, we want to obtain the average score of all the students in all the classes of a grade. According to the traditional method, we must use the AVG aggregate function to calculate the average score. The "disadvantage" is that we cannot easily return the columns (classes, students, and other columns) of the basic row, but can on
Reprint please indicate the source: http://blog.csdn.net/anxpp/article/details/51550479, thank you. 1. Overview
This article describes the string type and related functions, based on the current Oracle 12c.
The string is referred to as strings below.
There are two ways to work with Oracle functions:
1. Create new objects based on old objects-they modify the original information, such as changing the case of
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