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movq
V2EX  ›  MySQL

为什么 select (select row1 from table1) as row2,当 table1 为空时,结果是 null 而不是空呢?

  •  
  •   movq · Oct 3, 2022 · 2218 views
    This topic created in 1452 days ago, the information mentioned may be changed or developed.

    table1 为空, 所以 row1 为空。为什么select (select row1 from table1) as row2结果是 null 而不是空呢

    1 replies  •  2022-10-03 17:04:11 +08:00
    leonshaw
        1
    leonshaw  
       Oct 3, 2022
    这是 scalar subquery
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