SQL Supported

This section provides information about the SQL statements that the XML driver processes, and about SQL standards and conventions that the driver supports:

SQL Statements

The SQL Engine included with the XML driver supports the following SQL statements:

NOTE: See the table at the beginning of this chapter for the SQL statements that the XML driver supports for the different types of supported file formats.

Extensions to SQL Standards

The XML driver uses SQL grammar that is compliant with entry level ANSI SQL-92. Table 14-6 summarizes significant extensions to the grammar.

Table 14-6. SQL Extensions 
Entry Level ANSI SQL-92 Extension
Relevant Standard or Convention
Aliasing table references
Intermediate level ANSI SQL-92
ANSI date, time, and timestamp literals
Intermediate level ANSI SQL-92
Dynamic parameter specification
Full level ANSI SQL-92
GUID literals
COM
Hex string literals
Full level ANSI SQL-92
Left Outer Joins
Intermediate level ANSI SQL-92
ODBC escape support
ODBC 3.0
Scalar functions
ODBC 3.0

Grammar Token Definitions

The tokens used in the XML driver SQL grammar are defined in the following sections:

Regular Identifiers

A regular identifier must begin with a letter and may not exceed 128 characters. In addition, all ASCII characters are converted to uppercase.

The following are examples of regular identifiers:

Delimited Identifiers

Delimited identifiers may not exceed 128 characters. A double quotation character can be embedded within the string by specifying two consecutive double quotation mark characters. A delimited identifier can span multiple lines. The body of a delimited identifier can contain any character except the newline character.

The following examples show delimited identifiers:

Integer Numbers

Examples of integer numbers are:

Real Numbers

Examples of real numbers are:

Character String Literals

Character string literals are delimited with single quotation mark characters. A single quotation mark character can be embedded within the string by specifying two consecutive single quotation mark characters. A character string literal can span multiple lines.

Examples are:

GUID Literals

A GUID uses the following format, where x is a hexadecimal digit: 

xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

Hex Literals

Hex literal values are introduced with an uppercase X followed by a single quoted string of hexadecimal characters.

Examples are:

Time and Date Literals

Date, time, and timestamp literals are date, time, and timestamp values surrounded by a standard prefix and suffix. Date literals are specified in a YYYY-MM-DD format. Time literals are specified in an HH:MM:SS format with an optional fraction component. Timestamp literals are a concatenation of date and time values.

Examples for ODBC and SQL syntax are shown in the following table.

Literal Type
ODBC Syntax
ANSI SQL-92 Syntax
Date Literal 
{d '1999-09-19'} 

date '1999-09-19'
Time Literal 
{t '11:11:11.225'} 

time '11:11:11.225'
Timestamp Literal 
{ts '1999-09-19 
11:11:11.225'} 

timestamp '1999-09-19 
11:11:11.225'
Timestamp Literal 
{ts '1999-09-19'} 

timestamp '1999-09-19'

NOTE: ODBC 1.x style ODBC escape sequences such as the following are not supported:

--(*VENDOR(Microsoft), PRODUCT(ODBC) ...*)--

SQL Operators and Symbols

Symbol
Description
Symbol
Description
':'
Colon
'<'
Less than operator
';'
Semicolon
`)'
Right parenthesis
'.'
Period
`='
Equal operator
','
Comma
`+'
Plus operator
'<>'
Not equal operator
`-`
Minus operator
'<='
Less than or equal operator
`*'
Multiply operator
'>='
Greater than or equal operator
`/'
Divide operator
`>'
Greater than operator
`?'
Dynamic parameter
`(`
Left parenthesis
   

Keywords for the XML Driver

A keyword may not be used as a regular identifier. For example, the following statement would generate a syntax error because INDICATOR is a keyword: 

SELECT INDICATOR FROM T1

You can, however, enclose a keyword in double quotation marks to form a delimited identifier. For example, the following statement is valid: 

SELECT "INDICATOR" FROM T1

Table 14-7 lists all of the keywords that are reserved for use in SQL statements or designated as potential future reserved words.

Table 14-7. Reserved Keywords 
ABSOLUTE
ACTION
ADD
AFTER
ALIAS
ALL
ALLOCATE
ALTER
AND
ANY
ARE
AS
ASC
ASSERTION
ASYNC
AT
AUTHORIZATION
AVG
BEFORE
BEGIN
BETWEEN
BIT
BIT_LENGTH
BOOLEAN
BOTH
BREADTH
BY
CALL
CASCADE
CASCADED
CASE
CAST
CATALOG
CHAR
CHAR_LENGTH
CHARACTER
CHARACTER_ LENGTH
CHECK
CLOSE
COALESCE
COLLATE
COLLATION
COLUMN
COLUMNS
COMMIT
COMPLETION
CONCAT
CONNECT
CONNECTION
CONSTRAINT
CONSTRAINTS
CONTINUE
CONVERT
CORRESPONDING
COUNT
CREATE
CROSS
CURDATE
CURRENT
CURRENT_DATE
CURRENT_TIME
CURRENT_ TIMESTAMP
CURRENT_USER
CURSOR
CURTIME
CYCLE
DATA
DATE
DAY
DAYOFMONTH
DAYOFWEEK
DEALLOCATE
DEC
DECIMAL
DECLARE
DEFAULT
DEFERRABLE
DEFERRED
DELETE
DEPTH
DESC
DESCRIBE
DESCRIPTOR
DIAGNOSTICS
DICTIONARY
DISCONNECT
DISTINCT
DOMAIN
DOUBLE
DROP
EACH
ELSE
ELSEIF
END
END_EXEC
EQUALS
ESCAPE
EXCEPT
EXCEPTION
EXEC
EXECUTE
EXISTS
EXTERNAL
EXTRACT
FALSE
FETCH
FIRST
FLOAT
FLOOR
FOR
FOREIGN
FOUND
FROM
FULL
GENERAL
GET
GLOBAL
GO
GOTO
GRANT
GROUP
HAVING
HOUR
IDENTIFY
IF
IFNULL
IGNORE
IMMEDIATE
IN
INDEX
INFO
INDICATOR
INITIALLY
INNER
INPUT
INSENSITIVE
INSERT
INT
INTEGER
INTERSECT
INTERVAL
INTO
IS
ISOLATION
JOIN
KEY
LANGUAGE
LAST
LCASE
LEADING
LEAVE
LEFT
LENGTH
LESS
LEVEL
LIKE
LIMIT
LOCAL
LOOP
LOWER
LTRIM
MATCH
MAX
MIN
MINUTE
MOD
MODIFY
MODULE
MONTH
NAMES
NATIONAL
NATURAL
NCHAR
NEW
NEXT
NO
NONE
NOT
NOW
NULL
NULLIF
NUMERIC
OBJECT
OCTET_LENGTH
OF
OFF
OID
OLD
ON
ONLY
OPEN
OPERATION
OPERATORS
OPTION
OR
ORDER
OTHERS
OUTER
OUTPUT
OVERLAPS
PAD
PARAMETERS
PARTIAL
PENDANT
POSITION
POWER
PRECISION
PREORDER
PREPARE
PRESERVE
PRIMARY
PRIOR
PRIVATE
PRIVILEGES
PROCEDURE
PROTECTED
PUBLIC
RCASE
READ
REAL
RECURSIVE
REF
REFERENCES
REFERENCING
RELATIVE
REMOVE
REPLACE
RESIGNAL
RESTRICT
RETURN
RETURNS
REVOKE
RIGHT
ROLE
ROLLBACK
ROUND
ROUTINE
ROW
ROWS
RTRIM
SAVEPOINT
SCHEMA
SCROLL
SEARCH
SECOND
SECTION
SELECT
SENSITIVE
SEQUENCE
SESSION
SESSION_USER
SET
SIGNAL
SIMILAR
SIZE
SMALLINT
SOME
SPACE
SQL
SQLCODE
SQLERROR
SQLEXCEPTION
SQLSTATE
SQLWARNING
STRUCTURE
SUBSTRING
SUM
SYSTEM_USER
TABLE
TEMPORARY
TEST
THEN
THERE
TIME
TIMESTAMP
TIMEZONE_ HOUR
TIMEZONE_ MINUTE
TO
TRAILING
TRANSACTION
TRANSLATE
TRANSLATION
TRIGGER
TRIM
TRUE
TYPE
UCASE
UNDER
UNION
UNIQUE
UNKNOWN
UPDATE
UPPER
USAGE
USER
USING
VALUE
VALUES
VARCHAR
VARIABLE
VARYING
VIEW
VIRTUAL
VISIBLE
WAIT
WHEN
WHENEVER
WHERE
WHILE
WITH
WITHOUT
WORK
WRITE
YEAR
ZONE

SQL Comments

ANSI SQL-92 standard comments (--) and C++ standard comments (/*...*/, //) are supported. Comments can be nested.

For example, in the following query columns col2, col3, and col4 are ignored:

SELECT col1 /* col1 comment */ 

/* 
	col2,	-- col2 comment 
	col3,	// col3 comment 
	col4,	/* col4 comment */ 
*/ 
FROM t1