间隔文本语法

以下语法用于 ODBC 中的间隔文本。

interval-literal ：：= INTERVAL [+|-] interval-string interval-qualifier

interval-string ：：= quote { year-month-literal | day-time-literal } quote

year-month-literal ：：= years-value |[years-value -] months-value

day-time-literal ：：= day-time-interval | time-interval

day-time-interval ：：= days-value [hours-value [：minutes-value[：seconds-value]]]

time-interval ：：= hours-value [：minutes-value [：seconds-value ] ]

| minutes-value [：seconds-value ]

| seconds-value

years-value ：：= datetime-value

months-value ：：= datetime-value

days-value ：：= datetime-value

hours-value ：：= datetime-value

minutes-value ：：= datetime-value

seconds-value ：：= seconds-integer-value [.[seconds-fraction]]

seconds-integer-value ：：= unsigned-integer

seconds-fraction ：：= unsigned-integer

datetime-value ：：= unsigned-integer

interval-qualifier ：：= start-field TO end-field | single-datetime-field

start-field ：：= non-second-datetime-field [ (interval-leading-field-precision ) ]

end-field ：：= non-second-datetime-field |SECOND[ (interval-fractional-seconds-precision) ]

single-datetime-field ：：= non-second-datetime-field [ (interval-leading-field-precision) ] |SECOND[ (interval-leading-field-precision [， (interval-fractional-seconds-precision) ]

datetime-field ：：= non-second-datetime-field |第二

non-second-datetime-field ：：= YEAR |MONTH |DAY |HOUR |分钟

interval-fractional-seconds-precision ：：= unsigned-integer

interval-leading-field-precision ：：= unsigned-integer

quote ：：= '

unsigned-integer ：：= digit...