Redis

SELECT Statements

The Provider for Redis is SQL-92 compliant. Below are some example SELECT statements.

1. Return all columns:

   SELECT * FROM Customers

2. Rename a column:

   SELECT [CompanyName] AS MY_CompanyName FROM Customers

3. Search data:

   SELECT * FROM Customers WHERE Country = 'US';

4. Return the number of items in a group:

   SELECT COUNT(*) AS MyCount FROM Customers

5. Return the number of unique items in a group:

   SELECT COUNT(DISTINCT CompanyName) FROM Customers

6. Summarize data:

   SELECT CompanyName, MAX(Balance) FROM Customers GROUP BY CompanyName

7. Retrieve data from multiple tables.

   SELECT Restaurants.name, Zips.city FROM Restaurants INNER JOIN Zips ON Restaurants.zipcode = Zips.id

   See JOIN Queries below for details.

8. Sort a result set in ascending order:

   SELECT City, CompanyName FROM Customers ORDER BY CompanyName ASC

9. Restrict a result set to the specified number of rows:

   SELECT City, CompanyName FROM Customers LIMIT 10

10. Parameterize a query to pass in inputs at execution time. This enables you to create prepared statements and mitigate SQL injection attacks.

    SELECT * FROM Customers WHERE Country = @param

Aggregate Functions

The provider supports SQL-92 summary functions.

COUNT

Returns the number of rows matching the query criteria.

SELECT COUNT(*) FROM Customers WHERE Country = US

COUNT_DISTINCT

Returns the number of distinct, non-null field values matching the query criteria.

SELECT COUNT_DISTINCT(City) AS DistinctValues FROM Customers

AVG

Returns the average of the column values.

SELECT CompanyName, AVG(Balance) FROM Customers GROUP BY CompanyName

MIN

Returns the minimum column value.

SELECT MIN(Balance), CompanyName FROM Customers GROUP BY CompanyName

MAX

Returns the maximum column value.

SELECT CompanyName, MAX(Balance) FROM Customers GROUP BY CompanyName

SUM

Returns the total sum of the column values.

SELECT SUM(Balance) FROM Customers WHERE Country = US

JOIN Queries

The Provider for Redis supports joins of multiple tables.

Joining Multiple Tables

You can join multiple tables just like you would in a relational database. Set SupportEnhancedSQL to True to execute these types of joins. The following examples use two tables: Restaurants and Zips.

The query below returns the Restaurant records that exist, if any, for each ZIP code:

SELECT z.city, r.name, r.borough, r.cuisine, r.zipcodeFROM Zips zLEFT JOIN Restaurants rON r.zipcode = z._id

The query below returns records from both tables that match the join condition:

SELECT z.city, r.name, r.borough, r.cuisine, r.zipcodeFROM Restaurants rINNER JOIN Zips zON r.zipcode = z._id

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)