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 connector:

SELECT {
  [ TOP <numeric_literal> | DISTINCT ]
  { 
    * 
    | { 
        <expression> [ [ AS ] <column_reference> ] 
        | { <table_name> | <correlation_name> } .* 
      } [ , ... ] 
  }
  { 
    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 
  | {RANK() | DENSE_RANK()} OVER ([PARTITION BY <column_reference>] {ORDER BY <column_reference>})
  | <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 [CData].[GoogleSpanner].Customer

Rename a column:

SELECT [TotalDue] AS MY_TotalDue FROM [CData].[GoogleSpanner].Customer

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

SELECT CAST(AnnualRevenue AS VARCHAR) AS Str_AnnualRevenue FROM [CData].[GoogleSpanner].Customer

Search data:

SELECT * FROM [CData].[GoogleSpanner].Customer WHERE CustomerId = '12345'

Return the number of items matching the query criteria:

SELECT COUNT(*) AS MyCount FROM [CData].[GoogleSpanner].Customer

Return the number of unique items matching the query criteria:

SELECT COUNT(DISTINCT TotalDue) FROM [CData].[GoogleSpanner].Customer

Return the unique items matching the query criteria:

SELECT DISTINCT TotalDue FROM [CData].[GoogleSpanner].Customer

Sort a result set in ascending order:

SELECT Name, TotalDue FROM [CData].[GoogleSpanner].Customer  ORDER BY TotalDue ASC

Restrict a result set to the specified number of rows:

SELECT Name, TotalDue FROM [CData].[GoogleSpanner].Customer LIMIT 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 [CData].[GoogleSpanner].Customer WHERE CustomerId = @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 Google Spanner.

    SELECT * FROM [CData].[GoogleSpanner].Customer WHERE PSEUDO = '@PSEUDO'

Aggregate Functions

For SELECT examples using aggregate functions, see Aggregate Functions.

JOIN Queries