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what is differece between union and union all

Answer Posted / shabanafazal

in case of 'union' the data of two tables are combined
together with no repetition where as incase of 'union all'
repetition of data is done e.g in table 'A' we have name
saad three times and in 'B' table name 'ssad' is present
one time then in case of 'union' 'saad' is appeard once
(when union of table 'A' and 'B' is done). where as in case
of 'union all' the name 'saad' will repeated four times.

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