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 :: Concat
Concatenates all of the given values that are not null. Accepts any number of values. The + operator can also be used to concatenate, but a null on either side of + makes the whole result null.
SQL :: Count
Returns the number of values in each group. Count(0) and Count(*) count the documents in each group.
SQL :: CountDistinct
Returns the number of distinct values in each group. Values are compared without regard to case unless caseSensitive is true.
SQL :: DateAdd
Adds offset intervals to a date/time value and returns the new date/time. Use a negative offset to subtract. Interval names are not case-sensitive.
SQL :: DateDiff
Returns the number of intervals between two date/time values (date2 minus date1). See DateAdd for the interval names.
SQL :: DateTime
Returns the server's current local date and time, formatted with the optional .NET date/time format string.
SQL :: DateTimeUTC
Returns the current UTC date and time, formatted with the optional .NET date/time format string. See DateTime for the format specifiers.
SQL :: Declare
Declares a variable for the rest of a script.
SQL :: Delete
Delete removes the documents that match the given criteria.
SQL :: Detach Schema
Removes a schema (namespace) from the database and moves its files to a folder.