SELECT (SQL Analytics)

Retrieves result sets from one or more tables.

Syntax

[ WITH with_query [ , ... ] ]
select_statement [ { UNION | INTERSECT | EXCEPT } [ ALL | DISTINCT ] select_statement, ... ]
  [ ORDER BY { expression [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [ , ... ] } ]
  [ SORT BY { expression [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [ , ... ] } ]
  [ CLUSTER BY { expression [ , ... ] } ]
  [ DISTRIBUTE BY { expression [, ... ] } ]
  [ WINDOW { named_window [ , WINDOW named_window, ... ] } ]
  [ LIMIT { ALL | expression } ]

While select_statement is defined as

SELECT [ hints , ... ] [ ALL | DISTINCT ] { named_expression [ , ... ] }
  FROM { from_item [ , ... ] }
  [ PIVOT clause ]
  [ LATERAL VIEW clause ] [ ... ]
  [ WHERE boolean_expression ]
  [ GROUP BY expression [ , ... ] ]
  [ HAVING boolean_expression ]

Parameters

• with_query

  One or more common table expressions before the main query block.These table expressions can be referenced later in the FROM clause. This is useful to abstract out repeated subquery blocks in the FROM clause and improves readability of the query.

• hints

  Hints help the SQL Analytics optimizer make better planning decisions. SQL Analytics supports hints that influence selection of join strategies and repartitioning of the data.

• ALL

  Select all matching rows from the relation. Enabled by default.

• DISTINCT

  Select all matching rows from the relation after removing duplicates in results.

• named_expression

  An expression with an assigned name. Denotes a column expression.

  Syntax: expression [AS] [alias]

• from_item

  A source of input for the query. One of the following:

  • Table identifier

    • [database_name.] table_name: A table name, optionally qualified with a database name.
    • delta.`<path-to-table>` : The location of an existing Delta table.

    You can specify a time travel version using TIMESTAMP AS OF, VERSION AS OF, or @ syntax after a table relation. See Query an older snapshot of a table (time travel) for details.

    • JOIN
    • Table-valued function
    • Inline table
    • Subquery

• PIVOT

  Used for data perspective; you can get the aggregated values based on specific column value.

• LATERAL VIEW

  Used in conjunction with generator functions such as EXPLODE, which generates a virtual table containing one or more rows. LATERAL VIEW applies the rows to each original output row.

• WHERE

  Filters the result of the FROM clause based on the supplied predicates.

• GROUP BY

  The expressions that are used to group the rows. This is used in conjunction with aggregate functions (MIN, MAX, COUNT, SUM, AVG) to group rows based on the grouping expressions and aggregate values in each group. When a FILTER clause is attached to an aggregate function, only the matching rows are passed to that function.

• HAVING

  The predicates by which the rows produced by GROUP BY are filtered. The HAVING clause is used to filter rows after the grouping is performed. If you specify HAVING without GROUP BY, it indicates a GROUP BY without grouping expressions (global aggregate).

• ORDER BY

  An ordering of the rows of the complete result set of the query. The output rows are ordered across the partitions. This parameter is mutually exclusive with SORT BY, CLUSTER BY, and DISTRIBUTE BY and cannot be specified together.

• SORT BY

  An ordering by which the rows are ordered within each partition. This parameter is mutually exclusive with ORDER BY and CLUSTER BY and cannot be specified together.

• CLUSTER BY

  A set of expressions that is used to repartition and sort the rows. Using this clause has the same effect of using DISTRIBUTE BY and SORT BY together.

• DISTRIBUTE BY

  A set of expressions by which the result rows are repartitioned. This parameter is mutually exclusive with ORDER BY and CLUSTER BY and cannot be specified together.

• LIMIT

  The maximum number of rows that can be returned by a statement or subquery. This clause is mostly used in the conjunction with ORDER BY to produce a deterministic result.

• boolean_expression

  Any expression that evaluates to a result type Boolean. You can combine two or more expressions together using the logical operators ( AND, OR ).

• expression

  A combination of one or more values, operators, and SQL functions that evaluates to a value.

• named_window

  Aliases for one or more source window specifications. The source window specifications can be referenced in the window definitions in the query.

Related articles

• CASE clause
• CLUSTER BY clause
• Common table expression (CTE)
• DISTRIBUTE BY clause
• GROUP BY clause
• HAVING clause
• Hints
• Inline table
• JOIN
• LATERAL VIEW clause
• LIKE predicate
• LIMIT clause
• ORDER BY clause
• PIVOT clause
• Sampling queries
• Set operators
• SORT BY clause
• Table-valued function (TVF)
• WHERE clause
• Window functions