FireDAC Components for Snowflake

Build 21.0.7958

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 component:

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 [DemoDB].[PUBLIC].Products
  2. Rename a column:
    SELECT [ProductName] AS MY_ProductName FROM [DemoDB].[PUBLIC].Products
  3. Cast a column's data as a different data type:
    SELECT CAST(Price AS VARCHAR) AS Str_Price FROM [DemoDB].[PUBLIC].Products
  4. Search data:
    SELECT * FROM [DemoDB].[PUBLIC].Products WHERE ProductName = 'Konbu';
  5. Return the number of items matching the query criteria:
    SELECT COUNT(*) AS MyCount FROM [DemoDB].[PUBLIC].Products 
  6. Return the number of unique items matching the query criteria:
    SELECT COUNT(DISTINCT ProductName) FROM [DemoDB].[PUBLIC].Products 
  7. Return the unique items matching the query criteria:
    SELECT DISTINCT ProductName FROM [DemoDB].[PUBLIC].Products 
  8. Summarize data:
    SELECT ProductName, MAX(Price) FROM [DemoDB].[PUBLIC].Products GROUP BY ProductName
    See Aggregate Functions for details.
  9. Retrieve data from multiple tables.
    SELECT Customers.ContactName, Orders.OrderDate FROM Customers, Orders WHERE Customers.CustomerId=Orders.CustomerId
    See JOIN Queries for details.
  10. Sort a result set in ascending order:
    SELECT Id, ProductName FROM [DemoDB].[PUBLIC].Products  ORDER BY ProductName ASC
  11. Restrict a result set to the specified number of rows:
    SELECT Id, ProductName FROM [DemoDB].[PUBLIC].Products 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 [DemoDB].[PUBLIC].Products WHERE ProductName = @param
See Explicitly Caching Data for information on using the SELECT statement in offline mode.

Pseudo Columns

Some input-only fields are available in SELECT statements. These fields, called pseudo columns, do not appear as regular columns in the results, yet may be specified as part of the WHERE clause. You can use pseudo columns to access additional features from Snowflake.

    SELECT * FROM [DemoDB].[PUBLIC].Products WHERE MyPseudocolumn = 'MyValue'
    

Copyright (c) 2021 CData Software, Inc. - All rights reserved.
Build 21.0.7958