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 driver:

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

1. Return all columns:
   

   SELECT * FROM Orders

2. Rename a column:
   

   SELECT [ShipCity] AS MY_ShipCity FROM Orders

3. Cast a column's data as a different data type:
   

   SELECT CAST(Freight AS VARCHAR) AS Str_Freight FROM Orders

4. Search data:
   

   SELECT * FROM Orders WHERE ShipCountry = 'USA'

5. Return the number of items matching the query criteria:
   

   SELECT COUNT(*) AS MyCount FROM Orders 

6. Return the number of unique items matching the query criteria:
   

   SELECT COUNT(DISTINCT ShipCity) FROM Orders 

7. Return the unique items matching the query criteria:
   

   SELECT DISTINCT ShipCity FROM Orders 

8. Summarize data:
   

   SELECT ShipCity, MAX(Freight) FROM Orders GROUP BY ShipCity

   See Aggregate Functions for details.
9. Retrieve data from multiple tables.
   

   SELECT a.Name, o.CloseDate FROM Accounts a, Opportunities o WHERE a.Id = o.AccountId

   See JOIN Queries for details.
10. Sort a result set in ascending order:
    

    SELECT ShipName, ShipCity FROM Orders  ORDER BY ShipCity ASC

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

    SELECT ShipName, ShipCity FROM Orders 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 Orders WHERE ShipCountry = @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 xBase.

    SELECT * FROM Orders WHERE Pseudo = '@Pseudo'