43 lines
1.5 KiB
Markdown
43 lines
1.5 KiB
Markdown
InfluxQL supports both single and double quotation marks, but they each function
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differently and serve different purposes.
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- [Single quotes](#single-quotes)
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- [Double quotes](#double-quotes)
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## Single quotes
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Use single quotation marks (`'`) in the
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[string literal](/influxdb/version/reference/influxql/#strings) and
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[timestamp literal](/influxdb/version/reference/influxql/#dates--times) syntax.
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In the following example, the `WHERE` clause evaluates the value of the `room` tag.
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Tags only contain string values, so the right operand of the predicate expression
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should be a string literal.
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```sql
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... WHERE room = 'Kitchen'
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```
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## Double quotes
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Use double quotation marks (`"`) to quote [identifiers](/influxdb/version/reference/influxql/#identifiers).
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Identifiers **must** be double-quoted in the following cases:
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- The identifier contains non-word characters.
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Word characters are defined as `[a-z,A-Z,0-9,_]`.
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- The identifier is case-sensitive.
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- The identifier contains [InfluxQL keywords](/influxdb/version/reference/influxql/#keywords).
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- The identifier begins with a digit.
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Double-quoted identifiers can also:
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- Contain any Unicode character except for a new line.
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- Contain escaped `"` characters (for example: `\"`).
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- Include [InfluxQL keywords](/influxdb/version/reference/influxql/#keywords).
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**While not always necessary, we recommend that you double quote identifiers.**
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> [!Important]
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> InfluxQL quoting guidelines differ from
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> [line protocol quoting guidelines](/influxdb/version/reference/syntax/line-protocol/#quotes).
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