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d0f60b4425
To avoid having to specify each spec by hand (which can miss specs to be added), the test infrastructure now performs classpath discovery so that each spec added, is automatically considered. Relates #40358
276 lines
5 KiB
Text
276 lines
5 KiB
Text
[role="xpack"]
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[testenv="basic"]
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[[sql-functions-conditional]]
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=== Conditional Functions
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Functions that return one of their arguments by evaluating in an if-else manner.
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[[sql-functions-conditional-coalesce]]
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==== `COALESCE`
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.Synopsis:
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[source, sql]
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----
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COALESCE(expression<1>, expression<2>, ...)
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----
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*Input*:
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<1> 1st expression
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<2> 2nd expression
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...
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**N**th expression
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COALESCE can take an arbitrary number of arguments.
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*Output*: one of the expressions or `null`
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.Description
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Returns the first of its arguments that is not null.
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If all arguments are null, then it returns `null`.
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[coalesceReturnNonNull]
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----
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[coalesceReturnNull]
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----
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[[sql-functions-conditional-ifnull]]
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==== `IFNULL`
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.Synopsis:
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[source, sql]
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----
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IFNULL(expression<1>, expression<2>)
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----
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*Input*:
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<1> 1st expression
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<2> 2nd expression
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*Output*: 2nd expression if 1st expression is null, otherwise 1st expression.
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.Description
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Variant of <<sql-functions-conditional-coalesce>> with only two arguments.
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Returns the first of its arguments that is not null.
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If all arguments are null, then it returns `null`.
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[ifNullReturnFirst]
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----
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[ifNullReturnSecond]
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----
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[[sql-functions-conditional-isnull]]
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==== `ISNULL`
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.Synopsis:
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[source, sql]
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----
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ISNULL(expression<1>, expression<2>)
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----
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*Input*:
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<1> 1st expression
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<2> 2nd expression
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*Output*: 2nd expression if 1st expression is null, otherwise 1st expression.
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.Description
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Variant of <<sql-functions-conditional-coalesce>> with only two arguments.
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Returns the first of its arguments that is not null.
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If all arguments are null, then it returns `null`.
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[isNullReturnFirst]
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----
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[isNullReturnSecond]
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----
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[[sql-functions-conditional-nvl]]
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==== `NVL`
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.Synopsis:
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[source, sql]
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----
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NVL(expression<1>, expression<2>)
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----
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*Input*:
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<1> 1st expression
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<2> 2nd expression
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*Output*: 2nd expression if 1st expression is null, otherwise 1st expression.
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.Description
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Variant of <<sql-functions-conditional-coalesce>> with only two arguments.
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Returns the first of its arguments that is not null.
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If all arguments are null, then it returns `null`.
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[nvlReturnFirst]
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----
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[nvlReturnSecond]
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----
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[[sql-functions-conditional-nullif]]
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==== `NULLIF`
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.Synopsis:
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[source, sql]
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----
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NULLIF(expression<1>, expression<2>)
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----
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*Input*:
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<1> 1st expression
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<2> 2nd expression
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*Output*: `null` if the 2 expressions are equal, otherwise the 1st expression.
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.Description
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Returns `null` when the two input expressions are equal and
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if not, it returns the 1st expression.
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[nullIfReturnFirst]
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----
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[nullIfReturnNull]
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----
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[[sql-functions-conditional-greatest]]
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==== `GREATEST`
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.Synopsis:
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[source, sql]
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----
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GREATEST(expression<1>, expression<2>, ...)
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----
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*Input*:
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<1> 1st expression
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<2> 2nd expression
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...
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**N**th expression
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GREATEST can take an arbitrary number of arguments and
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all of them must be of the same data type.
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*Output*: one of the expressions or `null`
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.Description
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Returns the argument that has the largest value which is not null.
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If all arguments are null, then it returns `null`.
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[greatestReturnNonNull]
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----
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[greatestReturnNull]
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----
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[[sql-functions-conditional-least]]
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==== `LEAST`
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.Synopsis:
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[source, sql]
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----
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LEAST(expression<1>, expression<2>, ...)
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----
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*Input*:
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<1> 1st expression
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<2> 2nd expression
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...
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**N**th expression
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LEAST can take an arbitrary number of arguments and
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all of them must be of the same data type.
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*Output*: one of the expressions or `null`
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.Description
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Returns the argument that has the smallest value which is not null.
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If all arguments are null, then it returns `null`.
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[leastReturnNonNull]
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----
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["source","sql",subs="attributes,callouts,macros"]
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----
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include-tagged::{sql-specs}/docs/docs.csv-spec[leastReturnNull]
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----
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