SQL
. WHERE:
All rows for which the predicate in the WHERE clause is True are affected (or returned) by the SQL DML statement or query.
Expression:
An expression is a combination of one or more values, operators, and SQL functions that evaluates to a value.
. Database
Data types and ranges for Microsoft Access, MySQL and SQL Server.
. Row:
If PARTITION BY is not specified, the function treats all rows of the query result set as a single group
INTEGER
NT:int is a primitive type. Variables of type int store the actual binary value for the integer you want to represent. int.parseInt("1") doesn't make sense because int is not a class and therefore doesn't have any methods. Integer is a class, no different from any other in the Java language.
. PRIMARY KEY:
A primary key is a field in a table which uniquely identifies each row/record in a database table.
. Query:
A query is a request for information from a database.
Querying databases:
A query is an inquiry into the database using the SELECT statement. Aquery is used to extract data from the database in a readable format according to the user's request.
Data:
Each column in a database table is required to have a name and a data type.
GROUP BY:
Expressions that are not encapsulated within an aggregate function and must be included in the GROUP BY Clause at the end of the SQL statement.
SELECT *
FROM: A SELECT statement retrieves zero or more rows from one or more database tables or database views.
Aggregate functions
In database management an aggregate function is a function where the values of multiple rows are grouped together as input on certain criteria to form a single value of more significant meaning or measurement such as a set, a bag or a list.
. Column:
In the context of a relational database, a column is a set of data values of a particular simple type, one for each row of the table. The columns provide the structure according to which the rows are composed.
. Relational database:
RDBMS is the basis for SQL, and for all modern database systems like MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access. A Relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd.
SQL:
SQL is a special-purpose domain-specific language used in programming and designed for managing data held in a relational database management system (RDBMS), or for stream processing in a relational data stream management system (RDBMS).
SEQUEL:
SQL is a special-purpose domain-specific language used in programming.
INSERT:
Syntax: There are two basic syntaxes of INSERT INTO statement as follows: INSERT IN TO TABLE_NAME (column1, column2, column3,...columnN) VALUES (value1, value2, value3,...valueN); Here, column1, column2,... columnN are the names of the columns in the table into which you want to insert data.
d. AVG:
The AVG() function returns the average value of a numeric column.
e. COUNT:
The COUNT() function returns the number of rows that matches a specified criteria.
. Table :
The CREATE TABLE statement is used to create a table in a database.
. CREATE TABLE:
The CREATE TABLE statement is used to create a table in a database.Tables are organized into rows and columns; and each table must have a name.
b. MAX:
The MAX() function returns the largest value of the selected column.
c. MIN: .
The MIN() function returns the smallest value of the selected column
f. COUNT (*):
The SQL COUNT function returns the number of rows in a table satisfying the criteria specified in the WHERE clause.
SUM
The SUM() function returns the total sum of a numeric column.
. ORDER BY:
The basic syntax of ORDER BY clause which would be used to sort result in ascending or descending order is as follows: SELECT column-list FROM table_name [WHERE condition] [ORDER BY column1, column2, .. columnN] [ASC. DESC]; You can use more than one column in the ORDER BY clause.