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{ identifier expr }  is ODBC escape syntax and is accepted for ODBC compatibility. The value is expr . The {  and }  curly braces in the syntax should be written literally; they are not metasyntax as used elsewhere in syntax descriptions. 

match_expr  indicates a MATCH  expression. See Section 12.10, “Full-Text Search Functions” . 

case_expr  indicates a CASE  expression. See Section 12.5, “Flow Control Functions” . 

## Temporal Intervals 

interval_expr  represents a temporal interval. See Temporal Intervals. 

interval_expr  in expressions represents a temporal interval. Intervals have this syntax: 

INTERVAL expr unit 

expr  represents a quantity. unit  represents the unit for interpreting the quantity; it is a specifier such as HOUR , DAY , or WEEK . The INTERVAL  keyword and the unit  specifier are not case-sensitive. 

The following table shows the expected form of the expr  argument for each unit  value. 

<img src='content_image/712745.jpg'>

MySQL permits any punctuation delimiter in the expr  format. Those shown in the table are the suggested delimiters. 

