• evgen@moonbone.local's avatar
    Fix bug#14186 select datefield is null not updated · 77723c24
    evgen@moonbone.local authored
    Date field was declared as not null, thus expression 'datefield is null'
    was always false. For SELECT special handling of such cases is used. 
    There 'datefield is null' converted to 'datefield eq "0000-00-00"'.
    
    In mysql_update() before creation of select added remove_eq_conds() call.
    It makes some optimization of conds and in particular performs conversion
    from 'is null' to 'eq'. 
    Also remove_eq_conds() makes some evaluation of conds and if it founds that
    conds is always false then update statement is not processed further.
    All this allows to perform some update statements process faster due to
    optimized conds, and not wasting resources if conds known to be false. 
    77723c24
sql_select.cc 287 KB