--echo # --echo # Update with value from subquery on the same table --echo # analyze table t1 persistent for all; let $q = update t1 set c1=(select a.c3 from t1 a where a.c3 = t1.c3); eval explain select * from t1; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update with EXISTS subquery over the updated table --echo # in WHERE + possibly sargable condition --echo # analyze table t1 persistent for all; let $c = c1 <2 and exists (select 'X' from t1 a where a.c1 = t1.c1); let $q = update t1 set c1=10 where $c; eval explain select * from t1 where $c; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update with EXISTS subquery over the updated table --echo # in WHERE + non-sargable condition --echo # analyze table t1 persistent for all; let $c = exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 >= 3; let $q = update t1 set c1=c1+10 where $c; eval explain select * from t1 where $c; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update with order by --echo # analyze table t1 persistent for all; let $c = exists (select 'X' from t1 a where a.c2 = t1.c2) and c2 >= 3 order by c2; let $q = update t1 set c1=c1+10 where $c; eval explain select * from t1 where $c; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update with a reference to view in subquery --echo # in settable value --echo # analyze table t1 persistent for all; let $q = update t1 set c1=c1 +(select max(a.c2) from v1 a where a.c1 = t1.c1); eval explain select * from t1; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update view --echo # analyze table t1 persistent for all; let $q = update v1 set c1=c1 + (select max(a.c2) from t1 a where a.c1 = v1.c1) +10 where c3 > 3; eval explain select * from v1; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update view with reference to the same view in subquery --echo # analyze table t1 persistent for all; let $c = c1 <2 and exists (select 'X' from v1 a where a.c1 = v1.c1); let $q = update v1 set c1=c1 + 1 where $c; eval explain select * from v1 where $c; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update view with EXISTS and reference to the same view in subquery --echo # analyze table t1 persistent for all; let $c = c1 <10 and exists (select 'X' from v1 a where a.c2 = v1.c2); let $q = update v1 set c1=(select max(a.c1)+10 from v1 a where a.c1 = v1.c1) where $c; eval explain select * from v1 where $c; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update with IN predicand over the updated table in WHERE --echo # analyze table t1 persistent for all; let $c = c2 in (select distinct a.c2 from t1 a where t1.c1=a.c1); let $q = update t1 set c3=c3+110 where $c; eval explain select * from t1 where $c; eval explain $q; --enable_info ONCE eval $q; --sorted_result select c3 from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update with a limit --echo # analyze table t1 persistent for all; let $q = update t1 set c1=(select a.c3 from t1 a where a.c3 = t1.c3) limit 2; eval explain select * from t1 limit 2; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp; --echo # --echo # Update with a limit and an order by --echo # analyze table t1 persistent for all; let $q=update t1 set c1=(select a.c3 from t1 a where a.c3 = t1.c3) order by c3 desc limit 2; eval explain select * from t1 order by c3 desc limit 2; eval explain $q; --enable_info ONCE eval $q; select concat(old_c1,'->',c1),c3, case when c1 != old_c1 then '*' else ' ' end "Changed" from t1; truncate table t1; insert into t1 select * from tmp;