SQL: Unterschied zwischen den Versionen
Aus informatikvs
| Zeile 36: | Zeile 36: | ||
;olap cube() rollup() | ;olap cube() rollup() | ||
== snippets == | == snippets == | ||
| − | dec(round(plan_mod, +2), 6, 2) | + | <pre> ... dec(round(plan_mod, +2), 6, 2)</pre> |
| + | <pre> ... date(a.abdagc+693594) = current_date </pre | ||
Version vom 2. Mai 2017, 12:39 Uhr
terms
- sql-ddl
- (Data Definition Language) das erstellen/ändern/löschen von datenbankstrukturen (tables, fields, views, ...)
- sql-dml
- (Data Manipulation Language) das erstellen/ändern/löschen des inhalts (daten) der datenbankstrukturen
- sql-dcl
- (Data Control Language) Transaktionskontrolle und Zugriffsberechtigungen
- sql-injection
- transaktionen
- attribut
- index
- commands
- such as "Select", "Insert", "Update", "Delete", "Create", and "Drop"
- tables
- are uniquely identified by their names and are comprised of columns and rows.
- columns
- contain the column name, data type, and any other attributes for the column.
- rows
- contain the records or data for the columns.
- the where-clause
- optional specifies which data values or rows will be returned (criterias: =, <>, <, >, >=, <=, like)
- tuple
- is a collection of one or more attributes or rows present in a table
- constraints
- are uses to limit the values of variables NOT NULL; UNIQUE; PRIMARY KEY; FOREIGN KEY; CHECK; DEFAULT
- subquery
- aggregat functions
- avg(); count(); count(dinstinct field); max(); ...
- scalar functions
- ucase(), lcase(), mid(), len(), left(), right(), round(), mod(), now()
- olap cube() rollup()
snippets
... dec(round(plan_mod, +2), 6, 2)
... date(a.abdagc+693594) = current_date </pre
