Azure Table Storage
SELECT 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>
]
]
}
<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
Return all columns:
SELECT * FROM NorthwindProductsRename a column:
SELECT [Name] AS MY_Name FROM NorthwindProductsCast a column's data as a different data type:
SELECT CAST(Price AS VARCHAR) AS Str_Price FROM NorthwindProductsSearch data:
SELECT * FROM NorthwindProducts WHERE Industry = 'Floppy Disks'Return the number of items matching the query criteria:
SELECT COUNT(*) AS MyCount FROM NorthwindProductsReturn the number of unique items matching the query criteria:
SELECT COUNT(DISTINCT Name) FROM NorthwindProductsReturn the unique items matching the query criteria:
SELECT DISTINCT Name FROM NorthwindProductsSummarize data:
SELECT Name, MAX(Price) FROM NorthwindProducts GROUP BY NameSee Aggregate Functions below for details.
Retrieve data from multiple tables.
SELECT Customers.ContactName, Orders.OrderDate FROM Customers, Orders WHERE Customers.CustomerId=Orders.CustomerIdSee JOIN Queries below for details.
Sort a result set in ascending order:
SELECT PartitionKey, Name FROM NorthwindProducts ORDER BY Name ASCRestrict a result set to the specified number of rows:
SELECT PartitionKey, Name FROM NorthwindProducts LIMIT 10Parameterize a query to pass in inputs at execution time. This enables you to create prepared statements and mitigate SQL injection attacks.
SELECT * FROM NorthwindProducts WHERE Industry = @param
Aggregate Functions
COUNT
Returns the number of rows matching the query criteria.
SELECT COUNT(*) FROM NorthwindProducts WHERE Industry = 'Floppy Disks'
COUNT(DISTINCT)
Returns the number of distinct, non-null field values matching the query criteria.
SELECT COUNT(DISTINCT PartitionKey) AS DistinctValues FROM NorthwindProducts WHERE Industry = 'Floppy Disks'
AVG
Returns the average of the column values.
SELECT Name, AVG(Price) FROM NorthwindProducts WHERE Industry = 'Floppy Disks' GROUP BY Name
MIN
Returns the minimum column value.
SELECT MIN(Price), Name FROM NorthwindProducts WHERE Industry = 'Floppy Disks' GROUP BY Name
MAX
Returns the maximum column value.
SELECT Name, MAX(Price) FROM NorthwindProducts WHERE Industry = 'Floppy Disks' GROUP BY Name
SUM
Returns the total sum of the column values.
SELECT SUM(Price) FROM NorthwindProducts WHERE Industry = 'Floppy Disks'
JOIN Queries
The Provider for Azure Table Storage 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)
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