1 – first-clause
FIRST value-expr Specifies how many records are in the record stream formed by the record selection expression (RSE). The value expression, value-expr, is a symbol or string of symbols used to calculate a value. The value expression in a FIRST clause must either be a positive number or a value expression that evaluates to a positive integer. The record stream cannot contain more records than the number specified by the value expression.
2 – relation-clause
context-var IN relation-name Declares context variables for a record stream or a loop. The context variable specifies a temporary name that identifies the record stream to the product evaluating the clause. You then use the context variable to refer to fields from that relation. The relation name specifies the relation from which CDO will take the records in the record stream.
3 – cross-clause
{ CROSS relation-clause } ... Allows you to combine records from two or more record streams. You join these records in combinations based on the relationship between the values of fields in each record stream. This combination is called a relational join. The relation clause declares context variables for a record stream or loop.
4 – with-clause
WITH cond-expr Allows you to specify conditions that must be true for CDO to include a record in a record stream. You specify any conditional expression in this clause. The record becomes part of a record stream only when its values satisfy the conditions you specified in the conditional expression (that is, only when the conditional expression is true). If the conditional expression evaluates to false or missing for a record, that record is not included in the record stream.
5 – reduced-clause
REDUCED TO value-expr ,... Allows you to eliminate duplicate values for fields in a record stream and to group the records in a relation according to unique field values. However, only using the REDUCED clause does not guarantee the sort order within groups and the results are unpredictable. To ensure specific order, use the SORTED BY clause. The value expression, value-expr, specifies a symbol or string of symbols used to calculate a value.
6 – sort-clause
{ } SORTED BY { [ ASCENDING ] value-expr } ,... { [ DESCENDING ] } { } Allows you to sort the records in the record stream by the values of specific fields. The value expression, or sort key, determines the order in which CDO returns records. The default for an initial sort key is ASCENDING. The default for subsequent keys is the specification for the initial key. The value expression, value-expr, specifies the value to sort by; this value is called the sort key.