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what is differece between union and union all
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Answer / samy
Union:
combine two tables and common values to be retrieved no
duplicate values
Union All:
All the values to be retrieved when combine two table.
(duplicate values)
| Is This Answer Correct ? | 10 Yes | 1 No |
Answer / shyam
Union: It will combine the output of two or more queries &
it will eliminate duplicate values.
Union all:It will combine the output of two or more queries
& it will not eliminate duplicate values.
| Is This Answer Correct ? | 6 Yes | 0 No |
Answer / ramesh raja
UNION: combine distinct values between two tables
UNION ALL : combine all values and also duplicates values
between the two tables
| Is This Answer Correct ? | 4 Yes | 0 No |
Answer / dinesh sharma
Union:Only Select Distinct Value
Union All:Select All Values Using Duplicate
All Selected Columns Must Have Same DataType
Example:
Table 1 : First,Second,Third,Fourth,Fifth
Table 2 : First,Second,Fifth,Sixth
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / 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.
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / dinesh waitage
1)Union is used to select distinct values from two tables
where as union all is used to select all values including
duplicates from the tables.
2)UNION - returns on Distinct rows/Slower in performance
UNION ALL.
| Is This Answer Correct ? | 1 Yes | 0 No |
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