SQL/MX 3.x Reference Manual (H06.22+, J06.11+)

SQL/MX Statements
HP NonStop SQL/MX Reference Manual—640322-001
2-146
Considerations for EXPLAIN
stmt-name
is the statement pattern that includes name or %, or S%, and so on with single
quotes.
The syntax for the EXPLAIN statement supports four output options. Table 2-3
summarizes the options.
For more information about the operators in the query execution plan, see the SQL/MX
Query Guide.
Considerations for EXPLAIN
Case Considerations
In most cases, words in the commands can be in uppercase or lowercase. The letter
following the OPTIONS keyword must be within single quotes and in lowercase.
Number Considerations
Costs are given in a generic unit of effort. They show relative costs of an operation.
When numbers are displayed as 0.01 for OPTIONS 'n' (or 0.0001 for OPTIONS
'e'), the numbers have likely been rounded up. However, if the numbers are zero, the
display shows “0”.
When trailing decimal digits are zero, they are dropped. For example, 6.4200 will be
displayed as 6.42 and 5.0 will be displayed as 5, without a decimal point.
Table 2-3. EXPLAIN Statement Options
Syntax Option Type Purpose
OPTIONS 'f' Formatted Provides the basic information contained in the query
execution plan. This information is formatted for
readability and limited to 79 characters (one line) per
operator.
OPTIONS 'n' Normal user Provides the most important information contained in
the query execution plan. This information is formatted
for readability and is the default output format.
OPTIONS 'e' Expert user Provides all the information contained in the query
execution plan. This information is formatted for user
readability.
OPTIONS 'm' Machine
readable
Provides all the information contained in the query
execution plan. This information is formatted for
machine readability (easy to parse with software
tools).