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…..)) result is reused by LOCATE() LEFT(), RIGHT() and SUBSTR() returned tmp_value pointing into the buffer passed by the caller, without owning it. When a merged derived column is used twice, e.g. LOCATE(a, x, a), the second evaluation of the same item comes from Item_str_func::val_int(), which passes a local buffer. tmp_value is re-pointed into that buffer, the buffer is freed on return, and the first result becomes dangling. Copy the result into tmp_value instead, as MDEV-32758 did for TRIM().
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LEFT(),RIGHT()andSUBSTR()returnedtmp_valuepointing into the buffer passed by the caller, without owning it. When a merged derived column is used twice, e.g.LOCATE(a, x, a), the second evaluation of the same item comes fromItem_str_func::val_int(), which passes a local buffer.tmp_valueis re-pointed into that buffer, the buffer is freed on return, and the first result becomes dangling.Copy the result into
tmp_valueinstead.