Database crossword puzzle (EN)

2. value in a field with no value
6. Symbols or keywords used to perform operations on data in SQL queries
8. Clause used to filter records
12. Aggregate function, that returns the biggest value within the selected column
14. A function that performs a calculation on a set of values, and returns a single value
15. Association between two or more database tables
16. A clause used to specify the number of records to return
18. A statement that is used to select data from a database
19. Aggregate function, that returns the total sum of a numerical column
22. An operator that displays a record if the condition(s) is NOT TRUE
23. A command used with UPDATE to specify which columns and values should be updated in a table
25. The most basic level of database normalization (___ ___ form)
29. Collection of related data consisting of columns and rows

1. Database programming language
3. A command used to update existing rows in a table
4. Operator that selects values within a given range
5. A field in one table, that refers to the primary key in another table
7. System for storing and managing data
9. Aggregate function, that returns the average value within the selected column
10. A set of values arranged in a table and has the same data type
11. constraint that is used to uniquely identify each record in a table
13. Aggregate function, that returns the smallest value within the selected column
17. A structural element of a database consisting of fields
20. A relational database system widely used
21. Aggregate function, that returns the number of rows in a set
24. An operator that displays a record if any of the conditions separated is TRUE
26. A keyword that returns all rows from the right table, and the matching records from the left table (___ join)
27. An operator that displays a record if all the conditions separated are TRUE
28. A keyword that selects records that have matching values in both tables (___ join)