Expressions

Table of Contents



Expressions can be used in the field list of a Select, in Insert values, in Update assignments and in Where clauses.

  • Numbers: 10, -6, 3.14159
  • Strings: 'single quoted' or "double quoted". A doubled quote ('It''s') is not supported. A quote that follows a backslash does not end the string, but the backslash is kept: 'It's' returns It's.
  • Null: null


Operator Meaning
+ Adds numbers. When either side is a string, the values are concatenated: 'Id: ' + 5 returns 'Id: 5'.
- * / Subtraction, multiplication and division.
% Remainder (modulo).
Bitwise exclusive-or. Use Pow for exponentiation.
( ) Grouping, with standard order of operations.

A null on either side of + makes the result null (null propagation). Concat skips nulls instead.

These are used in Where clauses and join ON conditions:
Operator Meaning
= Equal (strings are compared without regard to case).
!= Not equal. The <> form is not supported.
> >= < <= Numeric comparisons.
LIKE, NOT LIKE Pattern matching, see Like.
BETWEEN, NOT BETWEEN Range matching, see Between.

Comparison operators can only be used in WHERE and ON clauses. Elsewhere, use the boolean functions such as IsEqual, IsGreater and IsLike, which return 1 or 0.

-- A line comment.
SELECT Id, Name FROM WordList:Language -- A trailing comment.
/* A block
   comment. */


Use Declare to define a variable for the rest of the script. Variables are referenced with an @ prefix. Applications using the client API pass parameters the same way, see Client.
DECLARE @Language = 2
SELECT Text FROM WordList:Word WHERE LanguageId = @Language


Every SELECT needs a FROM clause. To evaluate expressions that don't read any documents, select from the built-in Single schema, which contains exactly one document.
SELECT 10 + 10 as Twenty, 'Hello' + ' ' + 'World' as Greeting, Guid() as Id FROM Single




SQL :: Round
Rounds a number to the given number of decimal places. Midpoint values are rounded to the nearest even number (2.5 rounds to 2).
SQL :: Scalar Functions
Scalar functions are evaluated once per row.
SQL :: Select
Select statements are used to read (or query) data from the database.
SQL :: Select Into
Creates a schema and fills it with the results of a SELECT.
SQL :: Session Variables
Settings that are scoped to the connected session.
SQL :: Set
Set changes a session variable.
SQL :: Sha1
Returns the SHA-1 hash of the value's UTF-8 bytes as a lower case hex string.
SQL :: Sha1Agg
Returns a single SHA-1 hash of all of the values in each group, as a lower case hex string. Useful for detecting changes to a set of documents.
SQL :: Sha256
Returns the SHA-256 hash of the value's UTF-8 bytes as a lower case hex string.
SQL :: Sha256Agg
Returns a single SHA-256 hash of all of the values in each group, as a lower case hex string. Useful for detecting changes to a set of documents.