Category: Database
The union of several queries
Subqueries
Aggregate calculations
1.1 Statistical functions The statistical functions are standard to SQL and allow the calculation of statistical results on the rows of a table. AVG (column) Average values SUM (column) Sum of values MIN (column) Minimum value MAX (column) Maximum value COUNT (column) Number of values in the column COUNT (DISTINCT…
The joins
Writing Conditions with WHERE
1.1 The conditional expression SQL determines on which lines will be performed an operation by means of a conditional expression in the WHERE clause. At each line of the table, the expression conditional is re-evaluated based on line-specific values. If the expression evaluates to TRUE, then the requested operation (SELECT,…
Querying tables with SELECT
Data manipulation language (DML)
Fundamentals of Relational Database
The union of several queries
Subqueries
Aggregate calculations

1.1 Statistical functions The statistical functions are standard to SQL and allow the calculation of statistical results on the rows of a table. AVG (column) Average values SUM (column) Sum of values MIN (column) Minimum value MAX (column) Maximum value COUNT (column) Number of values in the column COUNT (DISTINCT…
The joins
Writing Conditions with WHERE

1.1 The conditional expression SQL determines on which lines will be performed an operation by means of a conditional expression in the WHERE clause. At each line of the table, the expression conditional is re-evaluated based on line-specific values. If the expression evaluates to TRUE, then the requested operation (SELECT,…