OData

Statements

A SELECT statement can consist of the following basic clauses.

• SELECT

• INTO

• FROM

• JOIN

• WHERE

• GROUP BY

• HAVING

• UNION

• ORDER BY

• LIMIT

SELECT Syntax

The following syntax diagram outlines the syntax supported by the SQL engine of the provider:

SELECT { [ TOP <numeric_literal> | DISTINCT ] { * | { <expression> [ [ AS ] <column_reference> ] | { <table_name> | <correlation_name> } .* } [ , ... ] } [ INTO csv:// [ filename= ] <file_path> [ ;delimiter=tab ] ] { FROM <table_reference> [ [ AS ] <identifier> ] } [ , ... ] [ [ INNER | { { LEFT | RIGHT | FULL } [ OUTER ] } ] JOIN <table_reference> [ ON <search_condition> ] [ [ AS ] <identifier> ] ] [ ... ] [ WHERE <search_condition> ] [ GROUP BY <column_reference> [ , ... ] [ HAVING <search_condition> ] [ UNION [ ALL ] <select_statement> ] [ ORDER BY <column_reference> [ ASC | DESC ] [ NULLS FIRST | NULLS LAST ] ] [ LIMIT <expression> [ { OFFSET | , } <expression> ] ] } | SCOPE_IDENTITY() <expression> ::= | <column_reference> | @ <parameter> | ? | COUNT( * | { [ DISTINCT ] <expression> } ) | { AVG | MAX | MIN | SUM | COUNT } ( <expression> ) | NULLIF ( <expression> , <expression> ) | COALESCE ( <expression> , ... ) | CASE <expression> WHEN { <expression> | <search_condition> } THEN { <expression> | NULL } [ ... ] [ ELSE { <expression> | NULL } ] END | <literal> | <sql_function> <search_condition> ::= { <expression> { = | > | < | >= | <= | <> | != | LIKE | NOT LIKE | IN | NOT IN | IS NULL | IS NOT NULL | AND | OR | CONTAINS | BETWEEN } [ <expression> ] } [ { AND | OR } ... ]

Examples

1. Return all columns:

   SELECT * FROM Lead
2. Rename a column:

   SELECT [FullName] AS MY_FullName FROM Lead
3. Cast a column's data as a different data type:

   SELECT CAST(AnnualRevenue AS VARCHAR) AS Str_AnnualRevenue FROM Lead
4. Search data:

   SELECT * FROM Lead WHERE FirstName <> 'Bartholomew'
5. Return the number of items matching the query criteria:

   SELECT COUNT(*) AS MyCount FROM Lead
6. Return the number of unique items matching the query criteria:

   SELECT COUNT(DISTINCT FullName) FROM Lead
7. Return the unique items matching the query criteria:

   SELECT DISTINCT FullName FROM Lead
8. Summarize data:

   SELECT FullName, MAX(AnnualRevenue) FROM Lead GROUP BY FullName

   See Aggregate Functions below for details.

9. Retrieve data from multiple tables.

   SELECT Customers.ContactName, Orders.OrderDate FROM Customers, Orders WHERE Customers.CustomerId=Orders.CustomerId

   See JOIN Queries below for details.

10. Sort a result set in ascending order:

    SELECT Id, FullName FROM Lead ORDER BY FullName ASC
11. Restrict a result set to the specified number of rows:

    SELECT Id, FullName FROM Lead LIMIT 10
12. Parameterize a query to pass in inputs at execution time. This enables you to create prepared statements and mitigate SQL injection attacks.

    SELECT * FROM Lead WHERE FirstName = @param

JOIN Queries

The CData ADO.NET Provider for OData supports standard SQL joins like the following examples.

Inner Join

An inner join selects only rows from both tables that match the join condition:

SELECT Customers.ContactName, Orders.OrderDate FROM Customers, Orders WHERE Customers.CustomerId=Orders.CustomerId

Left Join

A left join selects all rows in the FROM table and only matching rows in the JOIN table:

SELECT Customers.ContactName, Orders.OrderDate FROM Customers LEFT OUTER JOIN Orders ON Customers.CustomerId=Orders.CustomerId

Date Literal Functions

The following date literal functions can be used to filter date fields using relative intervals. Note that while the <, >, and = operators are supported for these functions, <= and >= are not.

L_TODAY()

The current day.

SELECT * FROM MyTable WHERE MyDateField = L_TODAY()

L_YESTERDAY()

The previous day.

SELECT * FROM MyTable WHERE MyDateField = L_YESTERDAY()

L_TOMORROW()

The following day.

SELECT * FROM MyTable WHERE MyDateField = L_TOMORROW()

L_LAST_WEEK()

Every day in the preceding week.

SELECT * FROM MyTable WHERE MyDateField = L_LAST_WEEK()

L_THIS_WEEK()

Every day in the current week.

SELECT * FROM MyTable WHERE MyDateField = L_THIS_WEEK()

L_NEXT_WEEK()

Every day in the following week.

SELECT * FROM MyTable WHERE MyDateField = L_NEXT_WEEK()

Also available:

• L_LAST/L_THIS/L_NEXT MONTH

• L_LAST/L_THIS/L_NEXT QUARTER

• L_LAST/L_THIS/L_NEXT YEAR

L_LAST_N_DAYS(n)

The previous n days, excluding the current day.

SELECT * FROM MyTable WHERE MyDateField = L_LAST_N_DAYS(3)

L_NEXT_N_DAYS(n)

The following n days, including the current day.

SELECT * FROM MyTable WHERE MyDateField = L_NEXT_N_DAYS(3)

Also available:

• L_LAST/L_NEXT_90_DAYS

L_LAST_N_WEEKS(n)

Every day in every week, starting n weeks before current week, and ending in the previous week.

SELECT * FROM MyTable WHERE MyDateField = L_LAST_N_WEEKS(3)

L_NEXT_N_WEEKS(n)

Every day in every week, starting the following week, and ending n weeks in the future.

SELECT * FROM MyTable WHERE MyDateField = L_NEXT_N_WEEKS(3)

Also available:

• L_LAST/L_NEXT_N_MONTHS(n)

• L_LAST/L_NEXT_N_QUARTERS(n)

• L_LAST/L_NEXT_N_YEARS(n)

Predicate Functions

CEILING(value)

Returns the value rounded up to the nearest whole number (no decimal component).

• expression: The value to round.

CONCAT(string_expr1, string_expr2)

Returns the string that is the concatenation of string_expr1 and string_expr2.

• string_expr1: The first string to be concatenated.

• string_expr2: The second string to be concatenated.

CONTAINS(string_expression, string_search)

Returns true if string_expression contains string_expression, otherwise returns false.

• string_expression: The string expression to search within.

• string_search: The value to search for.

DATE(datetime_offset)

Returns the current date using the specified datetime_offset.

• datetime_offset: The datetime offset to use when retrieving the current date.

DAY(datetime_date)

Returns the integer that specifies the day component of the specified date.

• datetime_date: The datetime string that specifies the date.

ENDSWITH(string_expression, string_suffix)

Returns true if string_expression ends with string_suffix, otherwise returns false.

• string_expression: The string expression to search within.

• string_suffix: The string suffix to search for.

FLOOR(value)

Returns the value rounded down to the nearest whole number (no decimal component).

• value: The value to round.

FRACTIONALSECONDS(datetime_time)

Returns the decimal value that specifies the fractional seconds component of the specified time.

• datetime_time: The datetime string that specifies the time.

HOUR(datetime_time)

Returns the integer that specifies the hour component of the specified time.

• datetime_time: The datetime string that specifies the time.

INDEXOF(string_expression, string_search)

Returns the index location where string_search is contained within string_expression.

• string_expression: The string expression to search within.

• string_search: The search value to locate within string_expression.

ISOF(string_expression, string_type)

Returns true if the string_expression is assignable to type string_type, otherwise returns false.

• string_expression: The string expression to check the type of.

• string_type: The name of the type.

LENGTH(string_expression)

Returns the number of characters of the specified string expression.

• string_expression: The string expression.

MAXDATETIME()

Returns the latest possible datetime.

MINDATETIME()

Returns the earliest possible datetime.

MINUTE(datetime_time)

Returns the integer that specifies the minute component of the specified time.

• datetime_time: The datetime string that specifies the time.

MONTH(datetime_date)

Returns the integer that specifies the month component of the specified date.

• datetime_date: The datetime string that specifies the date.

NOW()

Returns the current datetime.

REPLACE(string_expression, string_search, string_replace)

Returns the string after replacing any found string_search values with string_replace.

• string_expression: The string expression to perform a replace on.

• string_search: The string value to find within string_expression.

• string_replace: The string value replace and string_search instances found.

ROUND(value)

Returns the value to the nearest whole number (no decimal component).

• value: The value to round.

SECOND(datetime_time)

Returns the integer that specifies the second component of the specified time.

• datetime_time: The datetime string that specifies the time.

STARTSWITH(string_expression, string_prefix)

Returns true if string_expression starts with string_prefix, otherwise returns false.

• string_expression: The string expression to search within.

• string_prefix: The string prefix to search for.

SUBSTRING(string_expression, integer_start [,integer_length])

Returns the part of the string with the specified length; starts at the specified index.

• expression: The character string.

• start: The positive integer that specifies the start index of characters to return.

• length: The positive integer that specifies how many characters will be returned.

SUBSTRINGOF(string_expression, string_search)

Returns true if string_expression contains string_expression, otherwise returns false.

• string_expression: The string expression to search within.

• string_search: The value to search for.

TIME(datetime_offset)

Returns the current time using datetime_offset.

• datetime_offset: The datetime offset.

TOLOWER(string_expression)

Returns the string_expression with the uppercase character data converted to lowercase.

• string_expression: The string expression to lowercase.

TOTALOFFSETMINUTES(datetime_date)

Returns the integer that specifies the offset minutes component of the specified date.

• datetime_date: The datetime string that specifies the date.

TOTALSECONDS(duration)

Returns the duration value in total seconds.

• string_duration: The duration.

TOUPPER(string_expression)

Returns the string_expression with the lowercase character data converted to uppercase.

• string_expression: The string expression to uppercase.

TRIM(string_expression)

Returns the string_expression with the leading and trailing whitespace removed.

• string_expression: The string expression to trim.

YEAR(datetime_date)

Returns the integer that specifies the year component of the specified date.

• datetime_date: The datetime string that specifies the date.