Group Blog Post 11/07/2008

• MySQL :: MySQL 5.0 Reference Manual :: 12.2.8.3 UNION Syntax

  Tags: mysql, Syntax, UNION

  • The column names from the first
    SELECT statement are used as the
    column names for the results returned. Selected columns listed
    in corresponding positions of each
    SELECT statement should have the
    same data type. (For example, the first column selected by the
    first statement should have the same type as the first column
    selected by the other statements.)
    

    
    

    
    If the data types of corresponding
    SELECT columns do not match, the
    types and lengths of the columns in the UNION
    result take into account the values retrieved by all of the
    SELECT statements. For example,
    consider the following:
    

  • You can mix UNION ALL and UNION
DISTINCT in the same query. Mixed
    UNION types are treated such that a
    DISTINCT union overrides any
    ALL union to its left. A
    DISTINCT union can be produced explicitly by
    using UNION DISTINCT or implicitly by using
    UNION with no following
    DISTINCT or ALL keyword.

• gchartrb's gchartrb-0.8 Documentation

  Tags: gchartrb, ruby, google, chart, doc, reference

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