geode-docs/developing/querying_basics/what_is_a_query_string.html.md.erb - geode - Git at Google

 ---
 title:  Building a Query String
 ---

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 <a id="what_is_a_query_string__section_1866AE6026DE4D66A2CD2363C1BC0406"></a>
 A query string is a fully formed OQL statement that can be passed to a query engine and executed against a data set. To build a query string, you combine supported keywords, expressions, and operators to create an expression that returns the information you require.

 A query string follows the rules specified by the query language and grammar. It can include:

 -   **Namescopes**. For example, the IMPORT statement. See [IMPORT Statement](../query_select/the_import_statement.html#concept_2E9F15B2FE9041238B54736103396BF7).
 -   **Path expressions**. For example, in the query `SELECT * FROM                                 /exampleRegion`,` /exampleRegion` is a path expression. See [FROM Clause](../query_select/the_from_clause.html#the_from_clause).
 -   **Attribute names**. For example, in the query `SELECT DISTINCT * FROM /exampleRegion p WHERE                             p.position1.secId = '1'`, we access the `secId` attribute of the Position object. See [WHERE Clause](../query_select/the_where_clause.html#the_where_clause).
 -   **Method invocations**. For example, in the query `SELECT DISTINCT * FROM /exampleRegion p WHERE                             p.name.startsWith('Bo')`, we invoke the `startsWith` method on the Name object. See [WHERE Clause](../query_select/the_where_clause.html#the_where_clause).
 -   **Operators**. For example, comparison operators (=,&lt;,&gt;,&lt;&gt;), unary operators (NOT), logical operators (AND, OR) and so on. See [Operators](../query_additional/operators.html#operators) for a complete list.
 -   **Literals**. For example, boolean, date, time and so on. See [Supported Literals](../query_additional/literals.html#literals) for a complete list.
 -   **Query bind parameters**. For example, in the query `SELECT DISTINCT * FROM $1 p WHERE p.status =                             $2`, $1 and $2 are parameters that can be passed to the query during runtime. See [Using Query Bind Parameters](../query_additional/using_query_bind_parameters.html#concept_173E775FE46B47DF9D7D1E40680D34DF) for more details.
 -   **Preset query functions**. For example, ELEMENT(expr) and IS\_DEFINED(expr). See [SELECT Statement](../query_select/the_select_statement.html#concept_85AE7D6B1E2941ED8BD2A8310A81753E) for other available functions.
 -   **SELECT statements**. For example, in the example queries above `SELECT *` or `SELECT DISTINCT *`. See [SELECT Statement](../query_select/the_select_statement.html#concept_85AE7D6B1E2941ED8BD2A8310A81753E) for other available functions.
 -   **Comments**. OQL permits extra characters to accompany the query string without changing the string's definition. Form a multi-line comment by enclosing the comment body within `/*` and `*/` delimiters; OQL does not permit nested comments. A single line comment body is all the characters to the right of `--` (two hyphens) up to the end of the line.

 The components listed above can all be part of the query string, but none of the components are required. At a minimum, a query string contains an expression that can be evaluated against specified data.

 The following sections provide guidelines for the query language building blocks that are used when writing typical <%=vars.product_name%> queries.

 -   **[IMPORT Statement](../query_select/the_import_statement.html)**

 -   **[FROM Clause](../query_select/the_from_clause.html)**

 -   **[WHERE Clause](../query_select/the_where_clause.html)**

 -   **[SELECT Statement](../query_select/the_select_statement.html)**

 -   **[OQL Aggregate Functions](../query_select/aggregates.html)**
	---
	title: Building a Query String
	---

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	The ASF licenses this file to You under the Apache License, Version 2.0
	(the "License"); you may not use this file except in compliance with
	the License. You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
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	<a id="what_is_a_query_string__section_1866AE6026DE4D66A2CD2363C1BC0406"></a>
	A query string is a fully formed OQL statement that can be passed to a query engine and executed against a data set. To build a query string, you combine supported keywords, expressions, and operators to create an expression that returns the information you require.

	A query string follows the rules specified by the query language and grammar. It can include:

	- Namescopes. For example, the IMPORT statement. See [IMPORT Statement](../query_select/the_import_statement.html#concept_2E9F15B2FE9041238B54736103396BF7).
	- Path expressions. For example, in the query `SELECT * FROM /exampleRegion`,` /exampleRegion` is a path expression. See [FROM Clause](../query_select/the_from_clause.html#the_from_clause).
	- Attribute names. For example, in the query `SELECT DISTINCT * FROM /exampleRegion p WHERE p.position1.secId = '1'`, we access the `secId` attribute of the Position object. See [WHERE Clause](../query_select/the_where_clause.html#the_where_clause).
	- Method invocations. For example, in the query `SELECT DISTINCT * FROM /exampleRegion p WHERE p.name.startsWith('Bo')`, we invoke the `startsWith` method on the Name object. See [WHERE Clause](../query_select/the_where_clause.html#the_where_clause).
	- Operators. For example, comparison operators (=,<,>,<>), unary operators (NOT), logical operators (AND, OR) and so on. See [Operators](../query_additional/operators.html#operators) for a complete list.
	- Literals. For example, boolean, date, time and so on. See [Supported Literals](../query_additional/literals.html#literals) for a complete list.
	- Query bind parameters. For example, in the query `SELECT DISTINCT * FROM $1 p WHERE p.status = $2`, $1 and $2 are parameters that can be passed to the query during runtime. See [Using Query Bind Parameters](../query_additional/using_query_bind_parameters.html#concept_173E775FE46B47DF9D7D1E40680D34DF) for more details.
	- Preset query functions. For example, ELEMENT(expr) and IS\_DEFINED(expr). See [SELECT Statement](../query_select/the_select_statement.html#concept_85AE7D6B1E2941ED8BD2A8310A81753E) for other available functions.
	- SELECT statements. For example, in the example queries above `SELECT ` or `SELECT DISTINCT `. See [SELECT Statement](../query_select/the_select_statement.html#concept_85AE7D6B1E2941ED8BD2A8310A81753E) for other available functions.
	- Comments. OQL permits extra characters to accompany the query string without changing the string's definition. Form a multi-line comment by enclosing the comment body within `/` and `/` delimiters; OQL does not permit nested comments. A single line comment body is all the characters to the right of `--` (two hyphens) up to the end of the line.

	The components listed above can all be part of the query string, but none of the components are required. At a minimum, a query string contains an expression that can be evaluated against specified data.

	The following sections provide guidelines for the query language building blocks that are used when writing typical <%=vars.product_name%> queries.

	- [IMPORT Statement](../query_select/the_import_statement.html)

	- [FROM Clause](../query_select/the_from_clause.html)

	- [WHERE Clause](../query_select/the_where_clause.html)

	- [SELECT Statement](../query_select/the_select_statement.html)

	- [OQL Aggregate Functions](../query_select/aggregates.html)