UNION Queries |
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A UNION query can be used to combine the output of two queries into a single recordset. That's pretty much what documentation says. But as always, it is important to read the small print: "By default, no duplicate records are returned when you use a UNION operation". That's right. To return ALL of the rows from two queries, always use the ALL predicate SELECT x,y,z FROM t WHERE Condition1 UNION ALL SELECT x,y,z FROM t WHERE Condition2 The query will run faster that way as well. Sorry if you already knew that one, but I didn't, until it tripped me up.
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