DOC: fix latex error build
BUG: Arithmetic, timezone and offsets operations affecting to NaT
Merge pull request #6873 from sinhrks/nat_convert

BUG: Arithmetic, timezone and offsets operations affecting to NaT
BUG: data written with to_sql legacy mode (sqlite/mysql) not persistent GH6846

Correction for missing commit of data into SQL database in legacy code and add test to avoid future regression.

Correct tests according to comments
Merge pull request #6875 from Acanthostega/master

BUG: data written with to_sql legacy mode (sqlite/mysql) not persistent GH6846
SQL: fix + test handling columns argument in read_table
ENH: Use Float64HashTable for Float64Index backend
Merge pull request #6879 from cpcloud/float64-index-enh

ENH: Float64Index now uses Float64Hashtable as a backend
ENH/TST SQL: add multi-index support to to_sql
ENH/TST SQL: add multi-index support to read_table
Merge pull request #6735 from jorisvandenbossche/sql-multiindex

ENH: SQL multiindex support
BUG: legend behaves inconsistently when plotting to the same axes repeatedly