There are two types of CQL: definition CQL for defining streams and queries, and data manipulation CQL that is used in the REGISTER QUERY and REGISTER QUERY_ATTRIBUTE clauses of definition CQL.

The following table lists the definition CQL.

Table 4-1 Definition CQL list

No.	CQL	Explanation
1	REGISTER STREAM clause	Defines a stream
2	REGISTER QUERY clause	Defines a query.
3	REGISTER QUERY_ATTRIBUTE clause	Specifies time division for a query. The query for which time division is to be used must be defined following this clause.

The following table lists the data manipulation CQL.

Table 4-2 Data manipulation CQL list

No.	Type	Explanation
1	Inquiry	Searches data in a relation or the stream defined in the REGISTER STREAM clause.
2	Stream clause	Converts data to be output into a stream.
3	Relation expression	Searches data in one or more relations and filters the results of the search.
4	SELECT clause	Specifies how the searched result (select expression) is to be output and acquires the search result as a relation.
5	FROM clause	Specifies one or more relations (relation references). Relations acquired by the FROM clause becomes the target of the WHERE or HAVING clauses.
6	WHERE clause	Specifies a search condition for a relation acquired by the FROM clause.
7	GROUP BY clause	Specifies the columns (grouped columns) in the relation acquired by the preceding clause. Grouping is performed on the specified grouped columns only.
8	HAVING clause	Specifies a search condition for a relation acquired by the FROM clause, WHERE clause, or GROUP BY clause. A search condition specified in the HAVING clause executes a logical operation, and only the true results are acquired as a relation.
9	UNION clause	Links together multiple SELECT clauses and executes them as a single CQL statement.
10	Selection list	Specifies one or more select expressions.
11	Select expression	Specifies the item to be output from a search result.
12	Aggregate functions	Calculates a value from multiple rows.
13	Column specification list	Specifies one or more columns.
14	Relation reference	Specifies the relation to be searched. Relation reference is specified using the FROM clause.
15	Window specification	Specifies how long stream data stays in a relation. Window specification is specified using a relation reference.
16	Time specification	Specifies a time unit.
17	Search condition	Executes a logical operation using the specified condition and acquires only true results as a new relation. A search condition is specified using the WHERE or HAVING clauses.
18	Comparison predicate	Specifies the condition for determining a true or false logical value.
19	Value expression	Specifies a value.
20	Constant	Specifies a constant.